No. An agency may not require the use of a specific form or a particular method (e.g., NextRequest, email), but it may strongly encourage the use of one. The PRA in RCW 42.56.080 provides that:
No official format is required for making a records request; however, agencies may recommend that requestors submit requests using an agency provided form or webpage.
The preferred form or method should be articulated in the agency's policy. The Attorney General’s Model Rules on Public Disclosure encourage an agency to make available a public records request form in order to protect both the agency and the requestor. Agencies are welcome to convert the request to the preferred form on their own initiative and may want to do so for tracking purposes.