There are Mods In Java Edition to take the screenshots and crop them automarically. The manual way requires a few things first.

1. Find the position to take the panorama from.

2. Video Settings

2.1 Hide the HUD. For Players using a keyboard Press F1. If you are In Bedrock Edition and without a keyboard you may also need to go to Video Setrings and turn on Hide Hand.

2.2 Make sure to put your FOV at 90° exactly (The reason for this is the image will be cropped later, if you are not cropping the image, other fov's will work better).

2.3 Minecraft's sky changes color at certain times of day. If you are having problems turn off fancy skies and add in your own sun/moon to the panorama image later.

3. Unplug your mouse and type in these commands taking a screen shot after each one (You can take a screenshot simular to hiding the HUD by pressing F2)

Commands:
panorama_0.png
/teleport @s ~ ~ ~ facing 0 0

panorama_1.png
/teleport @s ~ ~ ~ facing 90 0

panorama_2.png
/teleport @s ~ ~ ~ facing 180 0

panorama_3.png
/teleport @s ~ ~ ~ facing 270 0

panorama_4.png
/teleport @s ~ ~ ~ facing 0 -90

panorama_5.png
/teleport @s ~ ~ ~ facing 0 90

4. Finding and Cripping your image

4.1 Find your screenshots. In java there is a screenshots folder. For bedeock edition just find where your device puts them.

4.2. Cropping the image. Crop your image into squares (1:1 aspect ratio) and make sure they are centered and ONLY removing pixels from the longest sides of the image making it a square shaped image. (If your FOV was not 90° you will have to crop differently.)

Here is a tool to help you crop your screenshots:
https://squareanimage.com/squarecrop/

Just make sure to slide this all the way to the left.

5. Making Your Resoursepack
5.1 Java - Look up a tutorial on where the panorama images are because it is defferent per version, but it is ususllly packages as such: assets/minecraft/gui/panorama
with all the images in the panorama folder.
5.2 Java - Next you will need to make a pack.mcmeta file. This can be done in a .txt file.

Code (pack.mcmeta)
{
"pack": {
"description": "Write Your Description Here",
"pack_format": 5
}
}

The pack_format number depends on the minecraft version, but the file will still work.
Save the file as pack.mcmeta next to (not in) the assets folder.

5.3 Java - Zip the assets folder and the pack.mcmeta file. You can name it whaterver you want, this will be the name of your Resourse Pack.

5.1 Bedrock Edition - Look up a tutuorial on where the panorama images go, but as of 1.20 they go in textures/ui with all the images in the ui folder.

5.2 Bedrock Edition - Now you need to make a manifest.json file. This can be done in a .txt file.

Code (manifest.json)

{"format_version":1,
"header":{
"description" : "the description of the pack",
"name" : "Name of the Resoursepack",
"uuid" : "aaaaaaaa-aaaa-aaaa-aaaa-aaaaaaaaaaaa",
"version":[​1,0,0]},
"modules":[{
"description":"for some reason this does not appear in game",
"type" :"resources",
"uuid":"aaaaaaaa-aaaa-aaaa-aaaa-aaaaaaaaaaaa",
"version":[​1,0,0]}]
}

between the quotation marks with a's and -'s you need two different uuid's. I use a version 4 uuid here: https://www.uuidgenerator.net/
It is okay for it to have numbers in it. Make sure all a's and -'s are removed before pasting in the uuid's.
Save the file as manifest.json next to (not in) the textures folder.

5.3 Bedrock Edition - Zip the textures folder and the manicest.json file. You can name this file whatever you wan and it WILL NOT affect the name of your resoursepack. Rename the file with .mcpack after or replacing.zip.


6. Java - To use your Resoursepack open miencraft and go to the resoursepacks screen. Click on "Open Resourse Pack Folder". Now you can drag the Resoursepack ending in .zip you created earlier into this folder. CONGRATULATIONS! You are done.

6. Bedrock Edition - To Import your Rssoursepack either click on it, or select "Open With" and select "Minecraft". If manifest.json is correct it should import succesfully. CONGRATULATIONS! You are done.