Ask your DM.
The DM decides what sources are allowed in the campaign and what sources are not. When you find some list of spells somewhere which you would like to use, show it to your DM.
If DM says it's OK, you can use them.
If DM says no, you can't.
What "internet spells?"
You didn't say which "internet spell list" you mean. There is a lot of "home-brewed" D&D content flying around the internet. This is content which players designed themselves.
While there are some really great and well thought out ideas among home-brewed content, you will often find material which is badly balanced, only balanced within the context of the house rules of the group which made it up, or does not fit together well with other content from other sources.
Also be wary of using content designed for other editions of D&D. There were considerable rule changes between the editions which greatly affected game balance. That means that some content is hard to convert from one edition to the other.
When your group is not very experienced with the D&D rules yet, then you might not yet have the experience to judge what's balanced and what isn't. You are better off sticking to the spells:
- Found in any official material published by WotC
- That apply to the edition of D&D you are playing.