Can I use a mix of single and double page spreads in my document?

It depends on how the pages are arranged and which document style you use.

This works

A single page front cover, double page spreads for all the middle pages, and a single page back cover. Use a Book style to display it this way. (A Presentation style always displays as single pages.)

This doesn’t work

Mixing single and double page spreads within the middle pages. With a Book style, the viewer automatically rearranges these into double page spreads, so the layout won’t display as designed.