Certificate of residence vs. certificate of residency — which one to use, when and why? Please quote a reputable source.
According to Google Ngram Viewer, “certificate of residency” is not used in British English whereas in American English “certificate of residence” has been in great decline with the gentle rise of “certificate of residency” almost meeting it.
So I might answer if your audience is British you have no option but if your audience is American you can choose between the older British term and the newer All-American term (-:
(Disclaimer: I'm Australian and don't recall ever dealing with either such certificate.)
It would depend on the terminology used by the authority issuing the certificate. Both are used widely.
If you're talking about such certificates in general, I'd go with certificate of residency. Residency usually carries an official connotation, and can either be used to indicate the jurisdiction in which you currently live, the length of time you have lived there, or both. Residence is a bit broader, and can be taken to indicate just your current street address, for example.
I wouldn't use residence, but residency.