Add a custom field for giving a tip to delivery person

Site URL: http://www.restorationcider.com

We are now delivering locally during Covid-19, can I add a field to allow customers to leave a tip for the delivery driver? I would want it to go through with the rest of the check out. 

bumping this question up, because I have the same question!!

Bump! Also looking to add tip to checkout.

Here's what I did today for a client. It's not a perfect solution but it's a easy to implement.

1. Go to Commerce / Shipping
2. Add Shipping Option / Flat Rate
3. Name the option "Delivery"
4. Add a price.

Would it be possible to do the tip as a calculated shipping rate?

For e.g. what if I added weight to all of my items.  The weight in pounds would equal to the dollar amount to calculate the tip. See screenshot below, I don't know if this would work since I have a trial version at the moment.
 

Basically what it would be is:

Food Item = $10.00  , set the weight of the item to be Weight = 10 Pounds, so the tip would be $1.50 (based on 15%)

Food Item = 20.00 , set the weifht of the item to be Weight = 20 Pounds, sot the tip would be $3.00 (based on 15%)