read this -
Software documentation - Wikipedia[
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There are many types of documents you can create -
1) Business requirement document - plot of your project
- this contains client requirement and proposed model of your software (rough work and may be pseudo code)
2) Technical document - Actual code and screenshot
- this contains actual software code and its details , screenshots of your application
3) User guide - how to use this app?
- this is for your end user who wants to use your software, they should know features of your application and how to use it and also limitation of your app
4) Test case document
- this is for your testing team to let them know how to test this software
user guide can be reference for this, but separate documentation would be added advantage