VisiCalc, the first computerised spreadsheet, was released in 1979. Presumably there were non-computerised spreadsheets, actual large sheets of paper, used for calculations before that.

The tab character, along with record separators were present in the OG ascii block too, so they were probably always there.

My Mum's typewriters had a tab key too! You used to start a paragraph off with a tab. Personally I prefer not to.

30 odd years ago I used to teach IT skills - UK govt funded qualifications. For example the RSA Computing level 1 and 2 NVQs. RSA were the really old school based qualifications (the R is for Royal) and by old school, I mean that they were old school 30 years ago! So it was basically a typing exam.

Each folder of "evidence" - 12 units, two or three pieces of evidence each - was allowed something silly like three mistakes. A mistake includes a typo, spacing and other daft things. The units were spreadsheets, word processing, databases, email, fax and more. Each piece of evidence could be quite a lot of text. You might notice that I put two spaces after a full stop (period). That's an old habit and failure to do so is a mistake.

Obviously the world has moved on since. Did you know there are at least four types of tab stop these days? Left, right, centre and decimal. Few people know or even care about decimal tabs. You can avoid them in web dev style and use a table to emulate them, but I will notice!

Anyway the tab key is way older than IT.

(EDIT) It seems HN coalesces multiple spaces into one when displaying.

My bad. Also lotus 123.