The issue is I have to pay 100,000 Dollar to my supplier but the inventory I have is only for 60,000 Dollar so how can I enter a purchase invoice of an inventory I already sold. It’s making my accounting complicated.
Waiting for most relevant information.
Thanks
MufeeX
You can use starting balances. Enter everything as it was on the Start Date that you began using Manager.
Enter the amount you owed the supplier at that date, and enter the amount of inventory you had at that date.
Set starting balances for suppliers
https://www.manager.io/guides/7227
Set starting balances for inventory items
https://www.manager.io/guides/5497
More guides
https://www.manager.io/guides/
If you had missed to enter any purchase invoice, you can still create a purchase invoice for that date.
If you had any outstanding amount to be paid to a supplier before migrating your accounts to Manager, then use starting balances as suggested by @ShaneAU
Thanks Man 
I done with it Relief