* 일어나다 (il-eo-na-da): This is the most general way to say "get up," referring to getting up from a lying or sitting position. It's versatile and can be used in many situations.
* 일어나세요 (il-eo-naseyo): This is the polite form of "il-eo-na-da," used when speaking to someone older or someone you don't know well.
Therefore, depending on the context and politeness level required, you would use either 일어나다 or 일어나세요.