Add-on Installation :

• Download and save the (zip) add-on in a folder.
• Go to Blender > Edit > Preferences > Add-ons > Install 
• Find the folder, select the zip file and install the addon.

Add-on Features :

The add-on has four features i.e 

• Text Keying
• Percentage
• Countdown
• Text Shuffle 

How to use : 

Text Keying

• Add a text object, go to text animation option and select text keying.
• There you will find an option called Add Keyframe. This will allow you to make your text appear at a particular frame interval. 
• This feature can be useful in adding subtitles, video titles, credits or even quotes to a video in 3D viewport of Blender.

Percentage

• Add a text, go to text animation option and select Percentage.
• This feature works with an driver object of which the transformation data will be used do the percentage animation. 
• Add a plane and select this as driver object of the text.
• At 1st frame keyframe the scale x of plane in default value. Then at frame 30 scale this a bit on x axis and keyframe it again. 
• Then go to text animation option and select translation type as scale x. 
• Go to first frame and press set current of minimum value then go to frame 30 and click on set current of max value. This will tie up the minimum and maximum scale value of plane with text. 
• You can also add decimal value , minimum and maximum value to the percentage number.
• Prepend text will appear before the percentage number and Append Text will appear after the percentage number. 

Countdown

• Add a text, go to text animation option and select countdown.
• The start value and end value will tell at what number the countdown will start or end.
• Delay (in frames) basically set the speed of the countdown.
• Enabling reverse option will do the actual countdown otherwise it is always the count up system.
• Start frame will decide at what frame the countdown or count up will start.

Text Shuffle

• Add a text, go to text animation option and select Text Shuffle
• Write the word you want to shuffle in Final Text
• Character Count will tell how many characters would shuffle to create the final text.
• Shuffling Speed will control the speed of shuffle per frame. 
• If you turn off the Random option and turn on the Synchronous option the text will shuffle ascendingly in alphabetical order to create the word. 
• Start frame will tell at what frame shuffle animation will start.