Sign in to the same Apple ID on both devices
On iPhone, go to Settings
Tap your name
Tap iCloud
Turn on iCloud Backup if needed
On iPad, go to Settings
Tap your name
Tap iCloud
Turn on iCloud Drive
Turn on Apps Using iCloud for the apps you want synced
Go to Settings
Tap App Store
Turn on Automatic Downloads for Apps
On iPhone, download the apps you want
On iPad, open the App Store
Tap your profile icon
Tap Purchased
Download the same apps on iPad
Make sure both devices are connected to Wi-Fi
Keep both devices updated to the latest iOS or iPadOS version