The Yellow Heart on Snapchat is an emoji that appears next to the name of one of your Snapchat friends in the chat list. It signifies that you and that friend have been each other's "Best Friends" for a specified period. Best Friends are determined based on the frequency of your interactions with other users. 
How To Get Yellow Heart On Snapchat?
However, it's important to note that Snapchat has frequently updated its features and emojis, so some aspects may have changed since then. Nevertheless, I'll explain how the Yellow Heart used to work and the steps to achieve it.

Understanding Best Friends on Snapchat:

Snapchat's Best Friends feature is designed to highlight the people with whom you interact most frequently on the platform.
The number of Best Friends is typically limited to a maximum of three, and these are displayed in the Chat section of the app.
The more you interact with a specific friend (through Snaps, chats, video calls, etc.), the higher the chance of that person becoming one of your Best Friends.

The Best Friends list is private, and only you can see who is on your list. Your friends cannot see who your Best Friends are.

Yellow Heart Emoji:
Once you and another user have been each other's Best Friends for two consecutive weeks, the Yellow Heart emoji will appear next to their name in your chat list.

The Yellow Heart signifies a close and strong mutual connection on Snapchat, as both of you have consistently interacted with each other over the past two weeks.

Steps to Get the Yellow Heart on Snapchat:
To achieve the Yellow Heart status with a friend, you need to maintain consistent and frequent interactions with them on the platform. 

Here are some steps to increase your chances of getting the Yellow Heart:

A. Snapchat Streaks: Engage in Snapchat streaks with your friend. A streak is formed when you and your friend send each other Snaps consecutively for multiple days. The longer the streak, the more likely you'll become Best Friends.

B. Send Chats: Apart from sending Snaps, have regular chats with your friend on Snapchat. Frequent chats contribute to your interaction level and increase the chances of becoming Best Friends.

C. Video Calls: Utilize Snapchat's video call feature to have face-to-face conversations with your friend. Video calls are considered high-value interactions and can boost your Best Friends status.

D. Sharing Stories: Interact with your friend's Stories by viewing them and replying if possible. Engaging with their Stories shows your interest in their content.

E. Mutual Interaction: Make sure that the friend you want to become Best Friends with also interacts with you frequently. The Best Friends feature is reciprocal, meaning both users need to interact regularly with each other.

F. Be Genuine: Focus on building a genuine friendship and connection with your friends on Snapchat. Authenticity in your interactions will make your Snapchat experience more enjoyable and meaningful.

G. Avoid Cheating Methods: Snapchat is designed to promote genuine interactions. Using third-party apps or cheating methods to artificially boost your interactions may violate Snapchat's terms of service and could result in penalties or the loss of your streaks and Best Friends status.

Maintaining the Yellow Heart:
Once you have achieved the Yellow Heart status with a friend, maintaining it requires continued regular interactions. If either you or your friend's interaction levels decrease, the Yellow Heart may disappear.

Changes and Updates:
Snapchat is known for frequently updating its features and emojis. As such, the methods to achieve the Yellow Heart or any other status may change over time. It's always a good idea to check Snapchat's official support documentation or community forums for the most up-to-date information on how Snapchat's features work.

In conclusion, the Yellow Heart on Snapchat is an emoji that represents a strong and consistent mutual interaction between you and a friend over a two-week period. To get the Yellow Heart, maintain frequent interactions with your friend through Snaps, chats, video calls, and by engaging with each other's Stories. Remember, Snapchat's features are subject to change, so always refer to official sources for the latest information.