"Shall Issue" means that concealed pistol, known alternately/elswhere as concealed weapon and concealed carry, licenses "Shall" be issued by the govt. to individuals not precluded by law from owning or possessing firearms if they apply.
This means if any 21 y.o. citizen of the U.S. and resident of WA, or even a foreign national and non-resident if they jump through more hoops, applies for a Concealed Pistol License (CPL) in WA and they are not precluded from owning or possessing because of a criminal history, the state SHALL/must issue them a license.
Some states have MAY issue which means you must show cause (read your Sheriff likes you or is in favor of concealed carry) for needing a CPL before the authority will grant you one.
Here in WA and in many other states it is a right that you have as opposed to a privledge.
I hope that clears things up.
Go to Packing.org for a more comprehensive understanding of the law and which states are Shall/May/don't even think about it jurisdictions.
Terrific - thank you for the explanation and the link referral.