When starting a WordPress website, the first thing you need to understand is the difference between WordPress.org and WordPress.com.
Quick Comparison
With WordPress.org, you choose a website hosting service, arrange a domain name (www.mysite.com), install the WordPress code, and start writing your website content. Many website hosting companies offer an easy “one-click install” for WordPress.
With WordPress.com, your site lives on the WordPress.com platform. You set up an account, choose a look, and start writing your website content there. You’ll need to move to a paid plan, if you want to have your own domain name, and to prevent ads from appearing on your site.
WordPress.org
A WordPress.org website is much more under your control. You can add themes and plugins which may not be available on WordPress.com. You are free to choose the hosting services and add-ons which fit your budget. And you always have complete control of your website and your content. Web hosting services also generally include email hosting as well, so there need be no additional cost for your own @domainname.com email address. Ultimately, the WordPress.org way is probably less costly.
WordPress.com
With WordPress.com, your site lives on the WordPress.com platform and it will always live there. In order to have your own domain name and remove ads, you must choose from the range of paid plans available. If you want your own @domainname.com email address, that is an additional cost. What you can do with your website, and how it appears is limited by what is available to you on WordPress.com.
Recommendations
If you don’t have the appetite to manage your WordPress website yourself, and don’t wish to engage someone else to do so, then WordPress.com is probably the simpler approach.
My choice and recommendation is to start your WordPress website the WordPress.org way. This gives you space to grow and more control, longer term.