If you are unable to provide your passport, explain why and supply letters from employers (including start and finish dates), payslips, P60s, educational establishments or other government departments indicating your presence in the United Kingdom during the relevant period
If you read this list and don’t read anything else, it makes it sound like providing your passport is enough.
For some nationals, though, it’s not. But you’d need to read a few paragraphs below to find that out.