In order to successfully create your Apple developer account, you will need to set up two-factor authentication as per Apple's new requirements as of June 29, 2018. To set this up, you will need an Apple device to link to your account!
To set up two-factor authentication on your account:
If you're using an iPhone, iPad, or iPod Touch:
1) Log into your device using the Apple ID you're using for the developer account
2) Follow the below steps in turning on two-factor authentication:
3) Set up a trusted number for two-step verification. When you're logging into your Apple ID or developer account, a code will be sent to your connected Apple device OR if you do not have access to the device at that moment, you can send a verification code to the trusted phone number via call or text instead. 
If you do not see the option to turn on two-factor authentication, and only see the option for two-step verification, then two-step will need to be turned off before you can turn on two-factor.
To do that, you'll need to log into your Apple ID under appleid.apple.com. Under Security, you'll be able to follow the steps to turn off two-step verification. Follow this Apple article to turn off two-step and turn on two-factor: https://support.apple.com/en-us/HT207198
If you're using a Mac:
1) Make sure you're logged into your System Preferences with the Apple ID you're using for your developer account.
2) Follow the steps below to turn on two-factor authentication:
*If you do not see the option to turn on two-factor authentication, either you need to disable two-step verification, or your computer may be outdated, as older versions do not have this extra level of security feature. You will need to update your MacBook to newer version that supports it or use another Apple device for the set up.
Once two-factor authentication is set up...
1) Log into https://appleid.apple.com/ and you should see the device you turned two-factor authentication on under the Devices category.
2) Once that appears, you can go back to https://developer.apple.com/account/ and click Join Apple Developer Program and proceed with the enrolment!
Please note, enrolment in the program can take roughly 5 business days. Once the account is set up, you can grant EventMobi access to the account where we can then proceed with your branded app submission!