Ciao! 😀
The subjunctive in Italian is quite a tricky topic because yes, it is important. It's part of the grammar and it's used. But it's not used as much as you may think for two main reasons.
But when do you use it? Mostly it's used when it comes to thoughts, opinions, beliefs, hopes etc. therefore it's used with verbs such as
Credere To believe
Pensare To think
Sperare To hope
Supporre To suppose
and sometimes even
Volere To want
When it comes to written Italian (formal) it's quite important to use it. But when it comes to speaking, it's mostly used with the verb "to be". For the other verbs, since it can create confusion since the first three conjugations (io, tu, lui) are often the same, it's often avoided.
I give you the link to the article where I discuss it even further and I provided some more information in Subjunctive in Italian.