File1.txt
phone_number
0777
0788
0789
0766
0756
File2.txt
phone_number name address
0777 Joe street1
0788 Karen street2
0789 Dave street3
0783 Sean street4
0781 Mick street5
Output required
phone_number name address
0777 Joe street1
0788 Karen street2
0789 Dave street3
Tried comm file1.txt file2.txt >comm2.txt
But the output shows there is no matching lines, because of the extra columns in file 2.txt.
Looked at a few awk scripts also but no joy getting desired output (common lines in each file with file2.txt extra columns included).