No. The notice must be written on paper. Your landlord cannot simply text or email you 90 days before they raise your rent and demand that you pay a new amount.
The rent increase notice I got gave me only 30 days advance written notice. Do I still have to pay the new amount?
State law at RCW 59.20.090(2) clearly states that the landlord must give you 3 months' notice. If you get a rent increase notice that gives you less time, talk to a lawyer right away. See contact info below.