It is not plagiarism if you write the following:
Your own ideas
e.g. "Firefox is the best web browser because I really enjoy using it."
Tip: Often you can make your own ideas look more convincing by supporting it with information from other sources, for example with a Techradar article in which the 7 most frequently-used browsers are compared. Then, of course, you give indicate the source again. General knowledge, e.g. "Chrome is a web browser."
General knowledge
e.g. "Chrome is a web browser."
Information from others (possibly in your own words) with correct reference
e.g. "Chrome was the most used web browser in 2018 (Statcounter, 2018)."
In the bibliography, you then include the complete reference:
"Statcounter (2017) Browser market share worldwide, retrieved from http://gs.statcounter.com/browser-market-share (2018, Nov 26)."