Greetings, jaleisha.
I see that the keyboard you're using on your iPhone 6s isn't responding as expected. The spacebar actually backspaces and predictive text doesn't always respond correctly either. I'm happy to help.
About the keyboards settings on your iPhone, iPad, and iPod touch -- If you're using a third-party, switch back to the keyboard for your country by tapping Settings > General > Keyboard > Keyboards. Test the issue if you changed keyboards. If the issue doesn't happen with the native keyboard, remove the third-party keyboard and restart your phone. When your phone returns to the Home screen, re-add the third-party and test the issue. If you're using the native keyboard, continue to the next step.
How to back up your iPhone, iPad, and iPod touch -- Since restarting your iPhone hasn't resolve the issue, please be sure to have a fresh backup to keep your personal information safe. In order to back up your Health data, the backup needs to be encrypted. iCloud does this automatically, but iTunes doesn't. If you'd like to use iTunes to back up your iPhone, refer to this article: About encrypted backups in iTunes
If you can't update or restore your iPhone, iPad, or iPod touch -- Even though the title of the article isn't specific to your issue, the section titled "Put your device in recovery mode and set it up again" will walk you through all the steps to reinstall the iOS software on your device. Test the issue once again.
Let me know how that goes, and take care!