Email Marketing

Well I have no idea if this is the right forum for it but If I have an email list of 500 cold emails that I've never encounterd before how do I email them and successfuly reach their inbox and not spam mail? is there any criteria ?

Your best bet is using a web based ESP like SendGrid. I think you can send this many even for free.
These ESPs are great because their ips are whitelisted, your only real job is to write a non-spammy email copy - most of them have a built-in checker to determine spam score - and you'll reach the inbox of all the major email providers.

Sendgrid, aweber, mailchimp - these will all do what you need - just make sure your emails have a clean code and no spam content

you can also try sparkpost email services they can allow you to send 100,000 emails per month free of cost. After approving your account they can even allow you to send 10,000 emails per day. This is absolutely free services. You can try this and really be surprised with them.