Good morning.How much to change battery IPhone 10 max thank you

Go to this web site for information about how to request battery service for your iPhone: iPhone Battery Repair & Replacement - Apple Support

For cost and availability, enter your model information in the "Get an estimate" box at the bottom. (It is best that you do this since sometimes price estimates posted by contributors here do not take into account that you may not be in the same country as the person providing the estimate.)

For instructions on how to get your iPhone, iPad, or iPod touch ready for service click here --> Get your iPhone, iPad, or iPod touch ready for service - Apple Support

Battery replacement on an iPhone 11 Pro Max is $89 if done in the U.S. by Apple. See the following for more information: iPhone Battery Repair & Replacement - Apple Support