I need to write an excel formula look for a value in a column and set the cell next to it

Question

I have two sheets in excel I need to check if the value next to my formula is equal to any of the first sheet first column, If yes I have to write the value next to it (sheet 1, column B, row where the value exists) otherwise I write "Does not exist"

which functions i have to use??

"lookup"

or

"Search"

or what ??

thank you for helping me

Answer 1

=IFERROR(VLOOKUP(A1,Sheet1!A:A,1,FALSE),"Does not exist")