I found that you can add a handling fee to your shipping rate
Go to shipping setting in setting and edit the rate
A merchant seeks to add a handling fee to transactions without using paid apps. Shopify staff explains there’s no native handling fee option in the admin, recommending alternatives like increasing product prices, adjusting shipping rates, or using product variants to reflect different handling costs. The concern is that additional checkout fees increase cart abandonment.
Workarounds discussed:
Ongoing frustrations:
The discussion remains open with no comprehensive native solution available as of 2025.