If you’re upgrading from a Mi Band to the Redmi Watch, you may want to transfer all your health and fitness data from the Mi Fit to Xiaomi’s Fitness app for Redmi Watch. Thankfully, it’s very easy and can be done as follows:
Step 1: Open the Mi Fitness app and go to the Profile section.
Step 2: Click on the (+) icon at the top right corner and select Settings.
Step 3: Now, select Transfer from Mi Fit and click on Transfer.
Step 4: Now login with your Zepp ID or other methods to transfer the data.
Source : wearablestouse.com