KGJams:
Simply increasing iCloud Storage has no affect upon Local (device) storage.
However, there are ways of setting up Apps to default to storing their files on iCloud, rather than defaulting to storing on the device's Local storage. (This is a longer term solution, and will respond to increases in iCloud Storage.)
First. Let's help you take care of the more immediate problem of freeing up Local Storage.
When you "go to 'General' then 'iPhone Storage'", it should offer some "RECOMMENDATIONS" for what you can do to help free up space:
- Offload Unused Apps (this goes along with what zinacef wrote.
- Review Downloaded Video files
- Review Photos
- etc.
Under those recommendations, there will be a listing (in decreasing size) of what Apps are taking up what space.
You can use that to guide you in what to remove, or whatever.
- An important thing to keep in mind is that just as with Computers (Macs or PCs), "Deleting" doesn't, necessarily, permanently remove the file, immediately: you have to take an additional step, like "emptying the Trash".
For the Longer Term, you can go to Settings->Apple ID (your name, at the top of the lefthand listing)->iCloud.
Below "Manage Storage" there is a listing of "APPS USING ICLOUD".
By default, many of those Apps will have iCloud Storage "turned off", but you can use the "switches" to turn iCloud usage on. (Some, like Photos, actually have a submenu of additional options you can set up, so things work the way you want them to.)
By turning on iCloud Storage, for many of your Apps, you can save Local Storage, since iCloud Files are only Cached on your device, as you use the files (on a file-by-file basis).
It also makes it easy to access those files on other machines and on iCloud, such as through a Web Browser.
Now. Just because you have turned on iCloud usage, for an app, doesn't, automatically, move already created filed out to iCloud: you'll use the particular App, or the Files App (looks like a Blue Folder on a White background) to move files over to iCloud.
(The operation will be called "Move", but, as of the last time I Moved files between Storage systems [like Local vs. iCloud] the Move, typically, becomes a Copy operation. So. If you actually want to remove the file from your Local Storage, you'll need to perform a separate Delete.)
- An important thing to keep in mind is that just as with Computers (Macs or PCs), "Deleting" doesn't, necessarily, permanently remove the file, immediately: you have to take an additional step, like "emptying the Trash".
For Photos, the "Trash" is the "Recently Deleted" folder, within Photos.
For many other files, the "Trash" is the "Recently Deleted" folder that you will probably only see within the Files App, mentioned above.
Note, however, that that "Recently Deleted" folder is a merged "Trash" for not only your Local Storage but also most of your Cloud Storage providers (like iCloud Drive, Google Drive, and many others).
So. When using the Files App, within the "Recently Deleted" folder, you can hold your touch on a file and a popup menu will appear: the options will be Delete Now, Recover, and Info.
You can use Info to find what type of Storage space a given file is using.
Then you can decide what you want to do with that file.