This will most probably be because you installed WordPress with 000webhostapp in the configuration, easily modify this in your wp-admin once logged in select general then change both URL boxes to http://yoursite.com - do not use HTTPS this will cause issues.
So now I’ve changed the URL to my personal site and it will no longer load the 000webhostapp in the address bar.
Now if you made the mistake of using HTTPS then you’ll probably see something like this in your browser in-secure or the page might not even load!
Head back to the settings menu and REMOVE HTTPS and replace it with HTTP!
If you’d like to prevent HTTPS errors completely then I would recommend installing this plugin if using WordPress on a personal domain like yoursite.com instead of a free subdomain provided by 000webhost.com
Hit install now above and then activate it below.
Now if I visit my site no security warnings should appear because the script is forcing HTTP connection to prevent HTTPS errors if someone mistypes HTTPS for example.
If I type https the site loads over HTTP - https is completely ignored and removed by the script
Now the only time an error should appear is when logging into your administrator panel - it may suggest that the site is insecure - this is just a safety notice by browsers because the SSL certificate is assigned to 000webhostapp.com or the free subdomain provided by 000webhost.com and yoursite.com obviously doesn’t match it because they are two completely different things - so ignore this error - your site is fine https isn’t required.
If you are still a bit confused then post a thread and someone will help you and try to explain why or why you do not need HTTPS.
If you think you still want to use HTTPS and SSL then please upgrade to premium.
This will allow a proper SSL certificate to be installed and you can process credit card information and customers data securely.