Tap the Like button, ✅, on any new profile to express interest. If they Like you back you can instant message within the app in Chat.

If you discover someone especially special and want to show your sincerity and enthusiasm as well as match them even if they’re yet to Like you back, use Instant Match tapping the ⚡ button on a profile.
What is Instant Match? If you discover someone especially special and want to stand out from the crowd, buy an Instant Match. This also enables you to match with someone before they’ve Liked you back.

Tap the ⚡ button on any profile that you haven't matched previously to buy an Instant Match.

It's free for them to reply and you can send as many messages as you wish.

If you’ve been Instant Matched you’re still in full control. If the matcher isn’t suitable simply Unmatch them from the More menu (the ••• button top right of any Chat).