Pamela, after removing the window, the framing will need to be reconstructed for a door opening. They are similar, but doors weigh more and the dimmensions are different. I recommend buying a pre-hung door as they are MUCH easier to install. Here's a link to a YouTuber who has the best construction advice: https://www.youtube.com/channel/UCzr30osBdTmuFUS8IfXtXmg
If you don't know how to do this it is best to call a contractor. It is not that easy of a task if you don't know how and why you are cutting into your house be it frame or brick.
Also check for electrical wiring. Wires may be running under window and will need to be re-routed over the door.