How to write smart scripts for structuring information on the Internet, looking for documents, searching for something / etc?

Question

Bots

How to write scripts for structuring information on the Internet, behind documents/etc?

I have long wanted to learn how to write scripts for Internet needs, but I don’t understand this at all.
In general, it would not hurt to have a general understanding of what language they can be written in, how to write them, because they, in theory, differ from the usual javascript scripts used purely on the page.

I'm talking about whole scripts that I can run in different programs similar in structure (browsers, as an example), and not built-in to one chrome, and is there any difference in this;
_smart_ scripts, bots, helpers, something like that.

For example, a script that will automatically save the tabs that I need in Google Spreadsheets, structuring them according to certain criteria;
a script to find names on the Internet according to criteria, displaying them in the field also according to such and such a structure