Sounds like you need help with your messaging. Might be a good idea to hire someone to help with that, not just a content writer but someone that can help you craft the message your audience needs.
The answer to this will highly depend on the structure of your WordPress theme.
- Some WordPress themes use a standard page without or without custom fields.
- Some themes use a widget based home page, which would require the user to make changes via the widget area of WordPress.
- Other themes may use a page builder, so you would need to access this add-on to make modifications and/or additions.
I would suggest you reach out to the developer of your WordPress template and/or visit their support forum and documentation to learn more about the specifics of your template.
Add it through the WYSIWYG, page builder or widget builder based on your theme
Personally, I like a minimal amount of content on the home page. Make sure your H1 header is succinct and optimized. Make sure you have descriptive <title> and <description> tags for SEO purposes. If you do decide to add more text content, perhaps consider adding excerpts which then link deeper into your site.