Since there's no ShareX/Screencloud or any other similar software for android, I wrote a few shell scripts to be used with termux to recreate at least some of the uploading functionality. Please note that I wrote this for my personal use (Linx+YOURLS), and a lot of modification will be needed if you end up using this for your own setup, but at least it's a good place to start. These scripts require termux, termux-api. After installing both run pkg update && pkg install termux-api curl jq and you should be ready go.
If entering them by hand on a phone or tablet, I recommend using Hacker's Keyboard which has arrow keys and a tab button for autocomplete.
$ pkg update
$ pkg install wget # termux come with busybox wget by default that doesn't support https
$ hash -r
$ wget https://github.com/zingmars/termux-scripts/archive/master.zip
$ unzip master.zip
$ pkg install vim #or nano or whatever editor you want
$ cd termux-scripts-master
$ chmod +x *.sh
# ! Edit your files, i.e. vim upload.sh
$ pkg install termux-api termux-tools curl jq
# Install the scripts
$ cd $HOME && mkdir bin && ln -s $HOME/termux-scripts-master/upload.sh $HOME/bin/termux-file-editor
$ ln -s $HOME/termux-scripts-master/delete.sh /data/data/com.termux/files/usr/bin/delete-file
$ ln -s $HOME/termux-scripts-master/shorten.sh /data/data/com.termux/files/usr/bin/shortenSimple upload script. Edit it's curl upload commands. Afterwards place it in termux's $HOME/bin/ rename it to termux-file-editor (or just symlink it) and then share your files to Termux like you would to any other app. A bit hackish, but it works.
Sends a DELETE request to an URL either passed as a parameter or from a file generated by upload.sh. Might not be needed for your host.
Shortens the passed URL. Uses a private YOURLS instance by default.