Documents for Naturalization

Hello,
Regarding the documents for naturalization, there is a requirement to show proof that you were in the UK for last 5 years. What proof generally we need to attach? As I don't have entry/exit stamps in the passport.

I am thinking of attaching last 5 years of P60 and a letter from employer confirming that I am working from this date to this date.

Thanks

Your passport will have been scanned by UK Border Force (Home Office). Just list your absences as best as you can.
UKVI have access to the database and validate what you submit. So no stamps in passport is not an issue and you don't have to explain, or provide alternative documents. UK ILR holders need only submit their passport scans.