Why should I use an order form?
Primarily, to make what's in your power to make such an important day go as planned. No one wants to see a ruined wedding (unless you're the bitter ex-boyfriend that still has feelings for the bride and expects a seconds chance now that he's done with cheating and gambling). This form will allow your business to collect (in astounding precision) every piece of information required to bring the cake of the happy couple's dreams to life.
Are the templates customizable?
How could they not be? Thankfully for everyone, the options are vast. Mess around with the colors, fonts, and design, and add every question you feel it's important, like medical conditions or allergies. A rash on the groom's wedding day would be devastating for the ones there (but great for the ex-boyfriend).
How can I use it?
Since it's an order form for a custom order, embedding the questionnaire to your company's website or social media pages is likely the best option to make sure it reaches your audience.