Once you’ve obtained an EIN, complete this eligibility worksheet and create a Pay.gov account before filling out Form1023-EZ, the streamlined application for 501c3 tax exemption for a cost of $275. If your organization is too large to be eligible for the streamlined form (with gross receipts of $50K or more and $250K or more in assets), you can fill out Form 1023 here for $600. 

You may want to assemble your articles of incorporation and bylaws into a single document before filling out and submitting Form 1023.