First, a personal comment, accepting credit cards is a cost of doing business and needs to be built into your markup and price, just like taxes, rent, workers comp, payroll, insurance.  It feels extremely tacky to charge an extra 3% to your customer and most if not all will not like it.

This is a complicated subject and the answer depends on quite a few things.  Most important to start with is this, Is it legal in your State. Colorado, Connecticut, Kansas, Maine, Massachusetts, Minnesota, New York, Oklahoma, and Texas all protect the customer from surcharges currently.  You also need to notify the credit card companies you are doing this.

you should definitely seek legal counsel as this is a legal question and I'm not a lawyer.

Here are other threads on this subject.

https://usa.visa.com/dam/VCOM/download/merchants/surcharging-faq-by-merchants.pdf

https://www.sellercommunity.com/t5/Questions-How-To/Surcharges-question/m-p/35973#M18075

https://www.sellercommunity.com/t5/Questions-How-To/How-do-I-add-a-surcharge-to-my-customers-bill/td...

https://www.sellercommunity.com/t5/Questions-How-To/Can-I-pass-the-credit-card-surcharges-on-to-the-...

https://www.sellercommunity.com/t5/Questions-How-To/Can-I-charge-clients-a-convenience-fee/m-p/19771...

https://squareup.com/help/us/en/article/5671-can-i-apply-a-surcharge-to-square-sales