When I am scanning one page and when I am going to second page it not connecting automatically I have to go to Scan pages click on add page it is taking long time to scan full document.
Yes, when you have 5 pages of a document to scan, you have to reselect the paper source and page size FOR EACH PAGE SCANNED. This is nuts.
Hope you are doing well. Sorry for the trouble.
I suggest you, please update the Adobe Scan application to the latest version.
Once that is done, check whether the Smart-Capture is enabled. [A camera button with the letter "A" on the left of the primary capture button].
This will enable the application to auto-adjust the page size demands and crop the portions automatically.
You may refer to the below links based on your platform:
For Android: Scan — Adobe Scan for Android
For iOS: Scan — Adobe Scan for iOS
Hope this helps.