Get Sheet/Tab name in Google Sheets

=REGEXREPLACE(CELL("address",Sheet2!A1),"'?([^']+)'?!.*","$1")

Sheet2!A1 = tab reference

Check below for a detailed explanation with pictures and how to use formulas in Google Sheets.

Get sheet name in Google Sheets

How to get sheet names in Google Sheets?
Get sheet name in Google Sheets

GET SHEET NAME IN GOOGLE SHEETS — GOOGLE SHEETS FORMULA AND EXAMPLE

=REGEXREPLACE(CELL("address",Sheet2!A1),"'?([^']+)'?!.*","$1")