Hi. My name is*****'m a camera repair technician with over 20 years in the business and I'll be glad to help you with your question today.
This is caused by dust and debris on the inside of the lens assembly, usually on the rear element or image sensor itself. This requires disassembling the camera to remove the lens assembly and then disassembling the lens mechanism to clean.
This really isn’t a user serviceable problem and should be repaired by a qualified technician. You may want to check locally for a camera repair shop in your area, or, if you need assistance finding a shop, please let me know and I'll locate one for you.