I dropped my phone and screen isnt showing on reno 2z how do I fix

Criszer, assuming your phone is still showing other signs of life such as ringing or vibrating when you call it, then yes, you would be fairly safe in assuming your screen has been damaged and is no longer working.

The procedure for replacing your screen is very similar to quite a few other Android phones in that there are two ways to do the job. The simplest and most recommended way is to replace the entire screen plus frame assembly as one piece. When you do it that way, you eliminate any difficulties with getting the new screen glued and sealed onto the frame, but it does mean you have to basically gut the phone; removing every component inside it and transferring them to a new frame assembly.

The good news about that is most phones that use this method are made for it; in other words the process is fairly straight-forward and simple. It's an order of magnitude easier than it would be to do, say, a housing replacement on an iPhone. In addition, the cost difference between a screen by itself and the screen+frame assembly is generally minimal; I don't remember seeing one where the cost was any more than about $5 USD, so that really shouldn't be a huge factor in making the decision on which method to use.

The other way to go about it is to remove the old screen from the frame and replace just the display. This generally means removing fewer parts since all you have to do is get to the display connector. However, that simplicity is offset by the need to clean all the old adhesive off the frame, then properly glue and clamp the replacement screen in place. As I mentioned, you will probably save a couple of dollars on the price, but that could well be made up for by the need to buy adhesive as well.

Anyway, sorry to say that iFixit doesn't have a guide for your phone, but there's a French site called SOSav that has exactly what you need to fix your phone.

Oppo Reno 2Z Screen Repair - Free guide - SOSav.fr

The site is in French, but if you use it with the Chrome web browser, the translation feature makes it very usable no matter what your native language is.

As far as locating a replacement screen, I usually start with the big sites like Amazon, eBay and AliExpress. There are likely others as well, but if you're using the guide posted above, you'll need to make sure the screen comes with the frame and not just by itself. As an example, here's a listing on AliExpress that has not only the bare screen and the screen+frame assembly, but also offers the option of buying a much cheaper TFT version (which, of course, will have a much lower quality picture and use quite a bit more power).

TFT AMOLED Display Touch Digitizer Assembly Replacement Screen, OPPO Reno 2, Reno 2F, 2Z, 100% Factory Well Tested - AliExpress

If you decide to go with the screen by itself, you can almost certainly find YouTube videos showing how to do that replacement, as the procedure for the two methods is completely different.

Good luck and let us know how it all turns out!