Enter, text expansion apps. These fabulous time-savers allow you to say more with fewer keystrokes. With text expansion apps, you can simply type in a short codeword, called an abbreviation that will then be replaced with a larger chunk of text, called a snippet. Others have pointed to low cost ones, but if your needs are very basic (just simple text substitutions) you already have text substitution! Go to System Preferences → Keyboard → Text and add whatever you want.
When you're working in jobs such as data entry then you'd be writing a lot of repetitive text on daily basis. In order to minimize the amount of keystroke you put in for same task, such apps are designed. You can use the auto-completion templates using one of the below mentioned programs and save your time. Apart from such template based expansion, there is also macro automation that you can do with such apps. If you're doing any writing work with repetition then such apps should be at your disposal.Text Expansion App Mac Download
Let's take a look at some of the apps that allow you to do the text expansion and auto completion. 
The original text expander for Mac.
Mac Apps Download
The original text expander for Mac.
Save time and effort. Type more with fewer keystrokes.
The very first text expander made for Mac, TypeIt4Me speeds up your typing by instantly replacing short abbreviations with longer snippets of text and / or pictures as you go along. Once the app is installed and launched, leave it running quietly in the background to help you type more quickly and accurately, with less wear on your fingertips.
Create shortcuts that expand to longer words, phrases or pictures.
Find yourself typing the same things over and over? Build up a set of abbreviations and the full text / image ‘snippets’ that they represent. TypeIt4Me will save you time and keystrokes by automatically expanding them while you continue typing. This works systemwide, in almost any app in which you can type.
Things TypeIt4Me can help you knock out more quickly include:
All your most frequently used phrases, boilerplate texts and pictures. Just a couple of taps away.
Text Expansion App Mac Ios
As well as expanding abbreviations you type, TypeIt4Me offers a handy point-and-click option. If you ever forget what abbreviation you assigned to a particular snippet, or even if you simply don’t feel like typing it, just scroll through the TypeIt4Me menu list and click it. The snippet contents will be inserted wherever the cursor is in whatever app you’re using.