Tell me if I’m wrong, but I think you want to know how to invert subject/verb in questions while using “Est-ce que” or “n’est-ce pas” to formulate the question.

If so, please note the following:

1) You need to invert subject and verb if you ask the question without those expressions, e.g.:

Aimes-tu voyager ? Oui, j’aime voyager.

2) If you decide to use “Est-ce que” to create your question, then there is NO inversion, e.g.:

Est-ce que tu aimes voyager ? Oui, j’aime voyager.

Note: You add “Est-ce que” at the beginning of the afirmative sentence, which makes it interrogative.

3) Almost the same goes for “N’est-ce pas”, except you add it at the end of the sentence, e.g.:

Tu aimes voyager, n’est-ce pas ? Oui, j’aime voyager.

Note: In that case, you ask the question but you have an idea of the answer. You’re asking for a confirmation.

For “D’accord”, I don’t think it’s really used. It seems more like an English expression literally translated into French.

Vous pouvez aussi dire:

N’est-ce pas que tu aimes voyager?

Est-ce que vous êtes étudiants?

D’accord que tu aimes manger au resto U?

I’m answering assuming that you can add one or two words as long as they help you use the suggested ones. e.g. That’s why I added the "que" in the last line.