Hi,
First of all, thank you for using my plugin. ??
As for your questions, well here are my brief asswers as well.
1.) You can adjust the size of that particular text by entering this CSS inside the Nifty Options -> General Settings -> Additional CSS:
.nifty-contact-details p {
font-size: 22px !important;
line-height: 24px !important;
}
This code will allow you to adjust the paragraphs in this section only. You can tweak the example values in pixels accoring to your needs.
2.) Nifty Coming soon plugin is sending the email using the WordPress build in mail function. So, if you are using the default WordPress setup, your WordPress website should send the messages using php_mail, if your messages are not being send, you might need to install some SMTP plugin like Easy STMP or similar. It will allow you to use real email address for sending message from your WordPress website as some host are not allowing php_mail on their servers.
I hope this was helpful enough.
If you find this plugin useful, please rate it with 5 star and support my work. ??
Thanks.