Is it possible to buy, and use bitcoin on mobile?

I have 0 knowledge on buying, using, and protecting myself when it comes to bitcoin.

I do not own a computer of any sort. I have an iPhone and want to purchase stuff safely, if there is a guide you can point me to it would be helpful. Or if you can take the time out of your night or day to help guide me, that would also be very appreciated. Thank you for your time.