Add Final Punctuation

How can I add final punctuation to all entries within a column? This is a pretty straightforward question, and I am disappointed that I couldn’t figure it out on my own. I just need to be able to add punctuation to the end of each cell within a particular column in my spreadsheet.

For example, I need to change something like:
“Hello world”
to “Hello world.”

Thanks for the help.

You can join a string to a string using +

So if your cells all contain strings and you want to add a period / full stop in all cases then you can use

value+"."

If you have more complex rules for when to add punctuation and what punctuation to add then please ask