Proofreading

Proofreading is an iterative process of comparing galley proofs against the original manuscripts or graphic artworks to identify transcription errors in the typesetting process. In the past, proofreaders would place corrections or proofreading marks along the margins. In modern publishing, material is generally provided in electronic form, traditional typesetting is no longer used and thus (in general) this kind of transcription no longer occurs. Consequently the part played by pure proofreaders in the process has almost vanished: the role has been absorbed into copy editing to such an extent that their names have become interchangeable. Modern copy-editors may check layout alongside their traditional checks on grammar, punctuation and readability.
— Wikipedia

I use digital tools for proofreading, such as LanguageTool with valentjn/ltex-ls) to write grammatically correct text in English and Russian.

A Pop Culture Guide to Proofreading Marks

Interesting cheat-sheet how to properly use proofreading marks, can be useful to visually proofreading my own texts.