Each contact has a personal card with all the details listed. If you need to edit some fields manually, follow these steps:
go to the People tab
click on any contact in the list
π‘ Important: if you add a link without any extra text in the field (for example LinkedIn, Company name, or any custom field), it can be opened in another tab using the CTRL + Click hotkeys on Windows or CMD + Click on Mac.
Once you have verified all the fields and links, make sure to click Save to apply the changes.
If you want to edit the contacts in bulk, use a CSV import with the new fields. You need to check the Update missing fields variant and the system will do the rest.