Hello @Kamileurocentrum
Please follow these steps to change the discount name on the cart page.
Step 1: Log in to your PrestaShop back office with the working credential.
Step 2: Go to Catalog >> Discounts Menu in the Sidebar panel after successful login. Please review the screenshot for reference(https://prnt.sc/qSyrjWDWKrAM).
Step 3: You will get all the discounts, and they will be listed on this screen.
Step 4: Now we need to change the Discount name, so click the Edit button here(https://prnt.sc/U19Lb_4LHMUu); if you have already created a discount rule and if not, then create a new discount rule by clicking on Add new cart rule button. For reference (https://prnt.sc/V6h6UL_GtmBE)
Step 5: Then you will get the field in which you have to change the discount name. for reference(https://prnt.sc/4Nb53J9ztGY6)
Step 6: Change the name and fill in all the required details. Then, click the save button, and the discount name will be displayed on the front end.
For, ie. I have already created a rule for discount, and the discount name is 15% for filters. Then, it will display something like this on the frontend cart page (https://prnt.sc/Ah1V-_Atjpme). If I want to change the discount name, then perform the above steps and change the discount name to 15% for the air purifier, it will be updated on the front end.
Please review the screenshot for your reference(https://prnt.sc/hHo1lbdOkoBV)
Hope this helps!
Thanks.