Pop up issue

I wanted to insert a popup with mailchimp but do not know where to enter the code, I tried to enter the code in the header area through widget but didnt workolso give me
give problems with the footer are.What can I do?

Hi @claudio,

I hope you are well today and thank you for your question.

You can try achieving this using any of the following plugins.

Best Regards,
Movin