Even if you use a platform such as ORCID to keep track of your works and activities, you may still need to keep a manual record of certain things if you wish to be able to refer to or quantify them later on your CV. This is because these are not easily tracked or counted.

It includes:

Outputs that are not in your ORCID (or other publication record systems). However, note that you can add a wide variety of works to ORCID (spin off companies, artistic works and more!), and you can toggle the visibility of individual works, meaning you can use it as a public AND private record. But if for some reason works are missing, keep a record of these so they don't get forgotten.
Outputs, uses or impacts that are not documented, or which do not have a link to a publication. This type of information is hard to track in online systems, but may reflect prestige, impact or societal value that you wish to keep track of.
Example: if you were invited/commissioned to write the publication; if you have given an interview/talk about a project; your work was used to support a change in practice or policy; your work formed the basis of a commercial application; your work was used in court cases.
Non-English language uses of your publications. Coverage of these is patchy (but improving) in databases such as Altmetric.
Example: uses of your work in Norwegian policy documents; a story about your work in a Norwegian newspaper
"Non-output" activities - Activities such as teaching, mentoring, supervising, leadership, and serving on committees can be valuable on a CV, but ORCID/Web of Science/Google Scholar are not good tools for recording them. Your UiB profile page is much more suited for showcasing these activities (read more about this on the next page). You might also want to keep a record of time you spend or other aspects:

"Rebecca Pillai Riddell, associate vice-president of research at York University in Toronto, Canada, always keeps meticulous track of time and effort spent on mentoring, teaching and serving on committees. “Nobody is going to track it for me,” she says. “To survive in academia, to get leadership roles, you have to advocate for yourself.”" - from Time to Rethink the Academic CV (Nature 2022)

Tip: Some people use a "master CV" for this kind of record keeping. The course FERD100 includes tips about keeping a master CV and your track record in Section 1, Academic CVs.