I Have recently started using Manager. I need to change my inventory quantities so it matches my stock on hand.
Write off inventory | Manager
Write on inventory | Manager
You need to investigate why your physical inventory does not match your inventory on hand.
Then you can adjust your procedures to avoid future mis-matches
Some stock I received as samples when buying equipment, some was bought from friends. I did not keep a record of all transactions.
I also did not keep a record of inventory write-offs
Your accountant and tax authority won’t be happy 
You need to record all transactions - otherwise if you are audited, you will have difficulty showing that your profit or loss was calculated in accordance with the tax rules. You could leave your business open to fines and/or prosecution if the differences are material.
You will have to enter a write-on or write-off transaction to adjust your stock to the correct amount
Thank you. 
Going to be busy for a while 