OK, you could create your web site content yourself. However, if your goal is to create a great, content rich site that will ultimately earn you an abundance of money I don't recommend you write it all yourself for two reasons.
The first reason is search engines love content. The more you can update your website the better. Can you keep supplying the search engines what they want on a regular basis? If not, it's a good idea to source the content from somewhere else.
The second reason is that if you are a prolific writer why not earn money writing instead of expending all your energy on your own content? You could create your own PLR business as part of your online empire and/or be a ghost writer and earn some money creating articles, ebooks and reports for others.
So, my recommendation is to use good quality private label content. It's hard to tell what's good quality before you purchase but usually it's cheap enough to take the risk. Many good PLR sites will offer you samples of PLR for free so that you check on the quality of their writers.
If you're not sure what PLR actually is, just watch the video below. Links to reputable PLR providers I use will be provided at the end of this page.
What Is PLR? This Video Explains.
Some places to get PLR content include:
PLR.me for unbelievably high quality personal development PLR including affirmations, articles and short reports
Resell Rights Weekly Great source of PLR and Resale Rights products. Free and paid memberships available.
Free Web Site Content
There are also many FREE sources of web site content.
For instance youtube (notice the video above....) If you're looking for articles do a search article directories and you'll heaps of free articles you can republish. The only condition is that you keep the author resource box intact. The reason author's allow you to republish their works is for back links to their websites.