Using other people's Icons

I am new to web design and would like to design websites for people in the future. I have done a few tutorials where the video uses icons from websites such as (I’m sure there are hundreds out there but this is the one I’ve been using for tutorials)

My question is when it comes to selling a website to a client, can I use these icons on the website I am developing, or do I have to design my own?

I have read the T & C’s on this website and it says that I can use them for commercial purposes and use them or edit them in any way I want, as long as I credit them…if this is the case where I can use the icons for free, where do I credit them, in the footer of my website? In the description in html?

Thanks in advance

You can credit them wherever you want, you can even create a page for credits, with a small link to it. But i`m sure there are lots of icons you can use without the need of crediting people that created them.

Yes you can use, but crediting will add value to someone’s hardwork. Also a ethical practice.

That seems fair enough!

I have downloaded the icons from flaticon, do I simply credit this website, or is it better to credit each author individually?