Any expert who can advise me about adding another name to my certificates, ID and all?
a lawyer
Changing your name on I.D or passport may be easier than certificates
fanya tu Deed Poll.
go to NSSF building, there is a department that deals with changes kwa ID. They will need proof as to why you want to change your names. You might need a police report like background check, birth certificate and any other legal and school documents . you might also need a sworn affidavit . But go there and ask them what they need. Its been awhile since i changed all those details and i don’t know if that department is still there
unless you want to change to meria kant help, labda uchukue Nef