Hi Chloe, Thanks for contacting us!
For commercial use (any use that generates a profit), it will be necessary to purchase the rights for any stickers you use on a logo. If you contact us here with details of which specific stickers you want to use, we’ll send you a link to purchase the stock images. They’re generally inexpensive.
As far as the fonts go, each font has different commercial use terms. You can check on these by clicking the little human icon at the top of the font list when on a particular font. There will be a link to the font designer’s website, and information on the price (if any) for a commercial license. These too are generally inexpensive or donationware.
Let us know if you have any further questions!