Adding 120 days to a date

I need to add a date to calc then add a recurring 120 days after,
or just add the 120 days to the date which I can then repeat,
ie in col 1A todays date, 9/2/24 then col 1B would be 120 days later
all help and advice appreciated

Sorry, there isn’t a column 1A nor a column 1B.
However, the more severe fact is that 9/2/24 isn’t a date at all, but just a slash-separated something (interpreted very differently, e.g, in the USA and the UK).
Todays date should look like 2024-02-09. Ignoring this kind of standardisation in spreadsheets causes problems again and again. Contributors to help sites like this one have wasted thousands of hours on this issue, and incorrect results in spreadsheets and data exchange based on “localised date formats” are legion.
Please reconsider your habits.

thank you Lupp, I enter the date as above then use formatting to set the full date as per UK, d/m/yyyy,
see attached regarding Columns 1A & 1B, this is how I refer to them, no idea on how you do it?
Karolus has answered my question

col ab.png

Hallo
enter:

=A1+120

into B1

thank you karolus, just what I was after, so simple