I translate your document, your ad, your website.
I translate your document, ad and website.
I'll assume you're writing to a customer. First, the verb tense needs to be modified.
I will translate... I have translated... I translated
So we'll use "will" and we have:
I will translate your document, your ad, and your website.
I will translate your document, ad and website.
The difference is only in the emphasis of pointing out that you doing all three things. For example, in verbal negotiation:
Customer: Your price is $150, but your competitor said he would translate my document for only $100.
You: But you need more than just the document translated, and you know I do good work. I'll tell you what. I'll translate your document, your ad, and your website all for only $120. I know my competitor can't beat that or my quality.
Another scenario, this time written:
Customer (posted work): I need the following translated: Document, Ad, and Website.
You (in writing, and wanting to be concise but specific): I will bid to translate your document, ad, and website for $120.