How can someone on IRR status go to Army OCS?

ARNG only don't know about USAR or Active Army

If you are under the age of 33 than you could still do active duty OCS in the ARNG. Research 09S which is the designation for OCS in the guard.

Find who is the state liaison for OCS and ask them the questions. They will recommend a recruiter to help you with the process.

Just some thoughts: I've noticed on here that freq those asking such questions often omit, if they're Assoc or Bach or masters or higher, which degrees they actually have. Also, freq, their major, desired field, and or MOS, or AFSC for USAF, etc. That being said, I'd certainly be most eager to offer thoughts, however , it'd obv be easier knowing as much as posbl a priori, that's all I'm saying. So, if you might be able to at all elaborate, as to exactly how much school you've had, and in what fields, and your ambitions, as well as how long you've been on active, whether you'd done any other SVC time, guard, or whatever, that'd also help, certainly. Next, I did see your said you were IRR, I folw, however do you have any preferences where you'd want to go after OCS, which branch, etc. Would you want to do grad school immediately, or part time, and, if so, in what area? It's just that the more specifics you can offer, then easier trying to help you or make sugstns might be, that's my only point. Having said that, I realize you want army, however, my thought is that you should apply for all of them. Also, I'm assuming youre prob mid to late 20s or early 30s, just as an assumption. Do you want flight at all, or ground? Also, do you have any clinical or technical interests, e.g., for the latter, engrg, comp sci, IT, physics, math, chem, etc.? To me, the more yupoumappky for, the greater your chance of getting something. I can perceive that you might think that you'd seem too scattered, however, when I was USAF OTS after army ROTC, and switching to USAF instead, there were many I knew at USAF OTS from other svcs, one guy was even Navy wearing enlisted dolphins. If you want clinical at all, or engrg, comp sci (CS), or IT, look also at usphs commissioned corps, as they do let engineers and health IT types be used, I'd read, even, I think, with CS backgrounds, at only Bach level. Then, too, depending on your age, vision, and interests, you could also look at NOAA commissioned corps, as well, which has an excellent flight program, though they're small, obviously. I'd also submit for USCG, and also USN, being as I'd read, espe, if you want a combat arms field, that USCG had been opened up to SEAL at one point, possibly also SWCC, as well. I'm not saying you need to, I'm merely mentioning possibilities, if your interests might perhaps run in such directions, and if your age and physical condition might qualify for being considered, that's all I'm suggesting. I'd be most eager to chat further, and most interested to hear more, whenever convenient, so far as you might be able to say, hope that was all of use. Also, if you're Assoc or Bach level, you could also consider WOCS for army, possibly, as well as, if you might have a suitable background, for OIS programs. I had a friend in a grad school program I was in for physics who was Navy OIS, he wore their t shirt constantly. If you went USPHS, they go by direct commission, and if assigned to USCG, or elsewhere, they have their own OIS programs, as well. Many thanks, most eager to hear further, if you might be interested in further chat.

You can go to Regular Army OCS. There are two to four OCS Boards a year that start with local level panels at the local recruiting battalion. I know because I was a recruiter and later transitioned to IRR to complete my degree and then pursued OCS.