We use a combination of Spreadsheets is a program called Maintenance Connect. But I work directly for a large end user with their own integrators. The maintenance Connect was not our choice but sort of forced onto us for asset management.
Otherwise we just have master tracking spread sheets for each individual site we look after, containing camera number (call up number in our VMS), patch panel number, switch port number, switch IP address, asset number (self generated number for our asset management for auditing purposes) MAC address, IP Address, Serial number, Model, brief description of location, etc.
We basically use the same series of password across our company for cameras, depending on the complexity required (some newer firmwares have forced us to use more complex passwords). But when I worked for private integrators I did include user name and password as well.
I did this for intrusion systems and access control as well. I'd have a template on my OneDrive, or Google Drive and edit as I got while doing the job. I thought it worked out quite well. Saved me from having to decipher my chicken scratches, or losing papers and such.