If you need our resources for personal use (not to sell), it is allowed to use them as the main elements of the final design you include in your products.
Please remember that the copyright of Flaticon resources belongs to its author (Flaticon), so you will not be able to register an image that includes any of our resources.
Also, if you are a free user, the attribution needs to be added to the product you create, even if this is for personal use. You can check how to do this from our attribution article.
As a premium member, you don’t need to credit the author when using the resources, but please remember to download the licenses.