I want to print 1000 coupons and distribute to customers. How can I generate 1000 coupons easily?

There is no need to generated 1000 different coupon codes for each coupon. MOSES allows limiting a coupon code to 1000 uses. All printed coupons will have the same coupon code. If there is really a need to have 1000 unique coupon codes, then use the Import Coupons function to import 1000 coupons using Excel. Refer to this for details.