I hope your day is going well, thanks for the question! This is definitely a strange situation as the Dawn 3.0 theme, as well as the rest of the Shopify developed themes, have a built in Add to Cart button that can only be removed by editing the code. Did you, or perhaps a developer edit the code for your theme to remove this button?
If you open your theme editor and select Product Information > Buy Buttons you will see you have the option to disable the Buy Now buttons and Express Checkouts, but not the Add to Cart button. Which is what leads me to believe this was edited in your code.
If you did hire a developer you should absolutely reach out to them to correct this. If not, you can use our guide to roll back your theme’s edits, or reinstall the Dawn 3.0 theme to your store. You will have to start from scratch, however it will be the default version of the theme without any code issues. In the meantime, welcome to the Shopify Community! Is this a new business? I would love to hear more.
I figured it out. My add to cart button was there but apparently a color the same as background and I couldn’t see it. Once I changed the color or border it was visible. Thank you