Do you have to be a Washington state resident to buy marijuana ?

No you dont need to be resident to purchase Cannabis just have a valid ID and be 21 +

What form of Identification are required to buy marijuana ?

All visitors must provide ID, whether you're 21 or 100, every time you visit. Forms of acceptable ID: US citizens must have a valid state-issued drivers license, or a US Passport, or Native American or Military ID. Non-US citizens must provide a valid Passport from your home country.

How much Marijuana can i buy at the time of my visit ?

Possession amounts you can Purchase any combination of the following from a licensed marijuana store:
+  One ounce of Flower/Bud 
+  Sixteen Ounces of Cannabis infused Product in Solid form ( Edibles )
+  Seventy two Ounces of Cannabis infused Product in Liquid form (Drinks)
+  Seven Grams of Cannabis Concentrate

Where can i smoke my Cannabis Legally

Just like with alcohol you can't smoke in public. You'll need to find a private home or cannabis friendly lodging in order to use your Cannabis. There are just a few hotels in Washington that have Cannabis smoking areas please contact you lodging  to ask if they are Cannabis friendly.

Can i take my Cannabis accrossed state lines ?

No. Any Cannabis you purchase in Washington State must be consumed in Washington state.  it’s a violation to transport your Cannabis accrossed state lines.  You can’t take it on a plane or send it through the mail.

Can i be charged with a DUI ?

Cannabis has intoxicating effects and can impair concentration and judgement can impairing
your ability to drive safely and endangering others. The legal limit is
currently anyone with 5 nanograms per milliliter of blood or  higher than
this will be charged with DUI when operating a motor vehicle