No.
A good translation company will:
1. Get the documents they need from you (copy of your passport, copy of your partner's ID card, the affirmation, etc.
2. Translate the affirmation document
3. Make an appointment for the legalisation at the MFA (or get an express appointment if time is short, at a cost)
4. Take the translation to the MFA and get the document legalised
5. Either contact you so that you can call into their office to collect everything, or post the documents back to you via EMS
This is the easiest, because all you have to do is attend the translation office at the beginning, supply the documents and pay. Up to you if you attend again in person to collect the documents.
Remember to take your passport and your partner's ID card with you when you attend the office. It will save all kinds of problems.
Personally, I use Express Translation which are located at BTS Chit Lom.
http://www.expresstranslationservice.co.th/cms.php?id_cms=6
https://maps.app.goo.gl/wVGBe3Uj6QLiC9d76
https://maps.app.goo.gl/NWXuG1vN45Ya2npo6