What is the role of PAGE section in windows Drivers?

Simple, it's a section that will supposedly be mapped as paged memory. This can contain code or data and is governed by the PAGED_CODE macro, among others, at source code level.

That is, whatever gets stored in that section cannot be accessed at arbitrary IRQLs. Quote:

If the IRQL > APC_LEVEL, the PAGED_CODE macro causes the system to ASSERT.

Also see this for an entry point into the overall topic. But I reckon given the specific nature of your question you are aware of paged and nonpaged pool and so on.