Jota + is the best text editor for Android.
Jota + is easy to use. And it has great skill and great performance.
For documentation, for programming, Jota + provides the best text editing experience.
+ Supports multiple file function.
+ Support 1 million characters.
+ Find / replace (supports regular expression)
+ Highlight search words.
+ Installation support-direct access function.
+ Auto save.
+ Show line numbers.
+ Show line break mark / tab.
+ Count characters / words / lines.
+ Customizable toolbar.
+ And it is customizable.
+ Customizable fixed phrase management.
+ Clipboard management.
+ Built in file browser with bookmark management.
+ Detect file modification.
+ Physical keyboard device support.
+ Bluetooth keyboard support.
+ Secure app without any wicked permission request.
+ Supports multi window function for Samsung devices.

Supported Android
(4.1 and up)
Ice Cream Sandwich (4.0 – 4.0.4),Jelly Bean (4.1 – 4.3.1),KitKat (4.4 – 4.4.4),Lollipop (5.0 – 5.1.1),Marshmallow (6.0 – 6.0.1),Nougat (7.0 – 7.1.1),Oreo (8.0-8.1), Pie(9.0)