Why Can’t I Save as JPEG in Photoshop?
Well, the answer is simple: you can, you just need to know where to look.
Why Can’t I Save as JPEG in Photoshop?
If you want to save something as a JPEG, you'll need to go to File, Export, and then Save for Web. Once you've selected that, you'll be able to choose JPEG from the drop-down menu.
Seems simple, right? But if you're a beginner, it can be a bit confusing because I'm assuming you're trying to export by going to 'Save As' - which won't let you export to web formats (except SVGs but that's besides the point).
One thing to keep in mind when saving as a JPEG is that you won't be able to save layers and effects. So, if you're wanting to save something with those features, you'll have to select a different file type.
Saving as a JPEG can be beneficial if you're wanting to upload images to the web. JPEGs are smaller in size and take up less space on your computer.
But, if you're using Photoshop for more advanced projects, you may want to opt for a different file type that can store layers and effects.
Conclusion
So, the next time you're confused as to why you can't save something as a JPEG, remember: you can, you just have to go to File, Export, Save for Web and select JPEG.