Match string in one column, return value in same row, skip rows that down't match

I have a data set where the column searched is always constant. I am trying to search the column for a specific string and return a value in the same row. I will use it for to return several different values. I tried several combinations of index and match but was not successful since the data is not a fixed amount of rows. It changes from time to time when the file is updated from an external program.

I can't get my file to upload so here is an example of a before and after.

Before:

1 A
2 A
3 B
4 C
5 D
6 A


Output: When searching for A

1 A 1
2 A 2
3 B 6
4 C
5 B
6 C


Output when search for B:

1 A 3
2 A 5
3 B
4 C
5 B
6 C

I hope this is clear. Thanks in advance for your help.

Thank you for your response.

I played around with what you have given and passed it into an index function to get the values that I needed.

Cheers,
Alex