OK, some more questions:
1. How are you making posts here, ie, what machine are you using? Given that you said "how i can check the model and Mac OS with out log in in on to it?", it seems like you are using another machine to post here. Is that correct?
2. Can you connect to the internet with the machine at your residence (assuming you can use it)?
3. To determine your Mac model, flip it over, and you should see some small "writing". Contained in that is the model number. For example, on my mid 2017 13" MacBook Air, it says "Mac Model A1466, EMC 3178". On my late 2012 Mac Mini, it says "Model No. A1347".
4. Is there anything that you need on the machine? The reason I ask is that if you reset the machine to its factory settings, it will involve completely Erasing and Re-Formatting the internal drive. Also, when you do that, you will need to go through a number of steps to set up the machine, ie, admin account name and password, Network and Internet settings, etc.
5. Just in case, do you have an external backup of all the information on the machine?
Once you answer those questions, we can help you better.