Quick Add allows you to quickly add friends on Snapchat. Quick Add lists all the users who are on your phone contact list, or with whom you have Snapchat friends in common.
Steps
Part 1 of 3: Allow Snapchat Access to Phone Contact List on iPhone or iPad

Step 1. Go to your iPhone settings
This is the application represented by a gray gear icon on the home screen.

Step 2. Tap Snapchat
The Snapchat app would be grouped together with your other apps on the bottom half of the page.

Step 3. Activate the Contacts option
It will turn green. From now on, Snapchat will be able to access all your phone contacts.
Part 2 of 3: Allow Snapchat Access to Phone Contacts on Android Device

Step 1. Go to your device's settings
This is the application represented by a gear icon (⚙️) on the Home screen.

Step 2. Scroll down and select Applications
This option can be found in the menu Device.

Step 3. Tap Permissions
This is the third option in the menu.

Step 4. Activate the Contacts option
It will take on a blue and green color.

Step 5. Tap the Back arrow in the upper left corner
From now on, Snapchat will be able to access all your phone contacts.
Part 3 of 3: Use Quick Add

Step 1. Open Snapchat
This is the application represented by a ghost icon on a yellow background. This will activate the camera.

Step 2. Swipe down on the screen to access the User menu

Step 3. Tap Add Friends
This button is located towards the center of the screen and has an icon representing a person with a sign +.

Step 4. Tap + Add next to a Quick Add user
- You can also open Quick Add by accessing the chats screen. That would be the title in blue letters under your friends list.
- If a Quick Add user has been added from your telephone contact list, the mention In my contacts will appear under their name.
Advice
- If you do not allow access to your contacts, Quick Add will continue to suggest users with whom you have common Snapchat friends.
- If you add someone using Quick Add, you will see the mention Added using Quick Add in his friend request.