Creating PowerPoint slides that summarize the essentials of your presentation is a key to effective communication.
It’s best to stick to one concept per slide, if possible. Focus on key words and phrases. It also pays to edit for brevity (try to use only nouns and verbs and to eliminate unnecessary verbiage.)
Also do not forget that people can read much faster than you can speak. This means that no-one will pay attention to your talk if everyone is just reading the content of your slides.
As a result, many presentation experts argue for the Rule of 7X7: no more 7 lines of text per slide and no more than 7 words per line. (Others argue for a 6X6 or 8X8 rule). Do not use bullets, except you present an enumeration!
Whatever combination suits you best, the general goal is to reduce wordiness and make it easy for your audience to comprehend the meaning of your message in that 5-7 second period of initial exposure to a slide.
The idea is to make it easier for your audience to see and comprehend your key message. These rules shouldn't be adhered to blindly. They are a way to bring some discipline to your presentation slides. Depending on the font you select, you may be able to use more words per line without losing effectiveness...