You normally tell whoever is fitting or supplying your pads the manufacturers part number for them to use as a cross reference to ensure they supply the correct pad.
Most suppliers websites also have the manufacturers number on them somewhere, again for use as a cross reference.
This is the Textar brakebook entry for your car:
brakebook.com - Textar
Click on 'More' for 3rd entry down (2431001) the ones decribed as 'for vehicles with AMG Sports Package) and then 'OE Reference' and you will see the manufacturers part number that these pads are equivalent to. NB the 4th entry down (2431081) are for the more expensive but dustless 'epad' versions.
If you just type the numbers straight into a Google search, it often produces supplier offerings. This is the second result in the list:
Genuine Mercedes-Benz W212 E-Class FRONT Brake Pads & Sensor A0074207520 NEW | eBay