Yes, you should wash all fabric you receive PRIOR to sewing with it!
Please use the highest heat setting, to both pre-shrink and also to disinfect any materials. Remember that masks need to be washed repeatedly with hot water settings.
Then, after your fabric is washed, iron and cut your fabric for your pattern.
We also recommend regularly wiping off / disinfecting your cutting board, tools, and work space, to stay well. And wash your hands frequently.