when creating appointment meet addin not display in outlook

Question

is there any way to show addin in appointment section or is it even possible or not?

Answer 1

Yes, it is possible. Take a look at the following sample markup from the manifest file which adds ribbon commands to the Appointment tab:

          <!-- Appointment compose form -->
          <ExtensionPoint xsi:type="AppointmentOrganizerCommandSurface">
            <OfficeTab id="TabDefault">
              <Group id="apptComposeDemoGroup">
                <Label resid="groupLabel" />
                <!-- Function (UI-less) button -->
                <Control xsi:type="Button" id="apptComposeFunctionButton">
                  <Label resid="funcComposeButtonLabel" />
                  <Supertip>
                    <Title resid="funcComposeSuperTipTitle" />
                    <Description resid="funcComposeSuperTipDescription" />
                  </Supertip>
                  <Icon>
                    <bt:Image size="16" resid="blue-icon-16" />
                    <bt:Image size="32" resid="blue-icon-32" />
                    <bt:Image size="80" resid="blue-icon-80" />
                  </Icon>
                  <Action xsi:type="ExecuteFunction">
                    <FunctionName>addDefaultMsgToBody</FunctionName>
                  </Action>
                </Control>
                <!-- Menu (dropdown) button -->
                <Control xsi:type="Menu" id="apptComposeMenuButton">
                  <Label resid="menuComposeButtonLabel" />
                  <Supertip>
                    <Title resid="menuComposeSuperTipTitle" />
                    <Description resid="menuComposeSuperTipDescription" />
                  </Supertip>
                  <Icon>
                    <bt:Image size="16" resid="red-icon-16" />
                    <bt:Image size="32" resid="red-icon-32" />
                    <bt:Image size="80" resid="red-icon-80" />
                  </Icon>
                  <Items>
                    <Item id="apptComposeMenuItem1">
                      <Label resid="menuItem1ComposeLabel" />
                      <Supertip>
                        <Title resid="menuItem1ComposeLabel" />
                        <Description resid="menuItem1ComposeTip" />
                      </Supertip>
                      <Icon>
                        <bt:Image size="16" resid="red-icon-16" />
                        <bt:Image size="32" resid="red-icon-32" />
                        <bt:Image size="80" resid="red-icon-80" />
                      </Icon>
                      <Action xsi:type="ExecuteFunction">
                        <FunctionName>addMsg1ToBody</FunctionName>
                      </Action>
                    </Item>
                    <Item id="apptComposeMenuItem2">
                      <Label resid="menuItem2ComposeLabel" />
                      <Supertip>
                        <Title resid="menuItem2ComposeLabel" />
                        <Description resid="menuItem2ComposeTip" />
                      </Supertip>
                      <Icon>
                        <bt:Image size="16" resid="red-icon-16" />
                        <bt:Image size="32" resid="red-icon-32" />
                        <bt:Image size="80" resid="red-icon-80" />
                      </Icon>
                      <Action xsi:type="ExecuteFunction">
                        <FunctionName>addMsg2ToBody</FunctionName>
                      </Action>
                    </Item>
                    <Item id="apptComposeMenuItem3">
                      <Label resid="menuItem3ComposeLabel" />
                      <Supertip>
                        <Title resid="menuItem3ComposeLabel" />
                        <Description resid="menuItem3ComposeTip" />
                      </Supertip>
                      <Icon>
                        <bt:Image size="16" resid="red-icon-16" />
                        <bt:Image size="32" resid="red-icon-32" />
                        <bt:Image size="80" resid="red-icon-80" />
                      </Icon>
                      <Action xsi:type="ExecuteFunction">
                        <FunctionName>addMsg3ToBody</FunctionName>
                      </Action>
                    </Item>
                  </Items>
                </Control>
                <!-- Task pane button -->
                <Control xsi:type="Button" id="apptComposeOpenPaneButton">
                  <Label resid="paneComposeButtonLabel" />
                  <Supertip>
                    <Title resid="paneComposeSuperTipTitle" />
                    <Description resid="paneComposeSuperTipDescription" />
                  </Supertip>
                  <Icon>
                    <bt:Image size="16" resid="green-icon-16" />
                    <bt:Image size="32" resid="green-icon-32" />
                    <bt:Image size="80" resid="green-icon-80" />
                  </Icon>
                  <Action xsi:type="ShowTaskpane">
                    <SourceLocation resid="composeTaskPaneUrl" />
                  </Action>
                </Control>
              </Group>
            </OfficeTab>
          </ExtensionPoint>

See https://github.com/OfficeDev/outlook-add-in-command-demo for the full sample code.

When creating or viewing an appointment or meeting as the organizer, add-in commands added to the default tab appear on the Meeting, Meeting Occurrence, Meeting Series, or Appointment tabs on pop-out forms. However, if the user selects an item in the calendar but doesn't open the pop-out, the add-in's ribbon group won't be visible in the ribbon.