Single command at the beginning of my Latex document that induces linebreaks?

Sample document:

documentclass[twocolumn]{article}

begin{document}

Some words words words.
In addition, the knowledge retention rate of the students also
increased by almost 12% when questions were reintroduced.

end{document}

The twocolumn option is meant to show the line break without making too long sentences.

According to the Webster dictionary, knowl-edge is the correct hyphenation in American English.

The British English hyphenation seems to differ (it's very common):

documentclass[twocolumn]{article}
usepackage[british]{babel}

begin{document}

Some words words words.
In addition, the knowledge retention rate of the students also
increased by almost 12% when questions were reintroduced.

end{document}

Now it's up to you to decide between US or UK English hyphenation rules and spelling. If you want to override the hyphenation and still use US English, add

hyphenation{know-ledge}

to your document preamble.

documentclass[twocolumn]{article}

hyphenation{know-ledge}

begin{document}

Some words words words. 
In addition, the knowledge retention rate of the students also 
increased by almost 12% when questions were reintroduced.

end{document}

The output will be the same as in the second picture above.