Here keep in mind when you upload any document, images and video inside your Post/Pages that image will automatically save in your WordPress media library and you can also use it anywhere you want. As you see in the above image there is a Add New button, here you can upload any image,video and documents file in Media Library if you are not willing to add this in your post. So you can use Add New Button to upload any file type in your Self hosted WordPress account.
If you want to get the URL of specific uploaded image then just click the image in your Media Library and you get the form Below.
In the File URL field > You can get the URL of that image and you can use this URL in your posts and anywhere in the internet. The same procedure will done with any document file types and videos.
Also Check : Difference Between Posts and Pages in Wordpress
You can also Crop and re sizing the image inside Media Library. Click the Edit Image option
and you get more options to Crop, Rotate, Resize and update Title, Alt Text and Description of your image.