Recently a new experimental feature, Container Control, has been released in Power Apps.

Container Control
Table of Contents
Once enabled an great update will be available to you from the Input menu. Note that it is still experimental, however this is a very valuable addition to the already great Power Platform.

When you add a container control to your app you will find quite quickly the benefits.
As shown below you can add controls to the container and initially you might think hat this is just the same as grouping with a new name.But a container is more.

Have you noticed the position of the Label1 control? it is set to X = 40 and Y = 40. This shows that the positioning is relative to the cotnainer ratehr than the screen.
Comparing this to the grouping of controls we will see that groups leave the controls inside a group use positioning relative to the screen.

Release a container
You can also release a container. This means that the container control is removed and the controls inside the container are positioned on the page again.

Converting groups into containers
Ok, many of your apps will have groups and these groups you may want t convert to containers as Containers will help you simplify your app. To do this select the group and then select the Add to container option.

This now converts the Group into a container and you can take advantage of the container control.

Nested Containers
Once you have created containers you can also create nested containers. All the same relative positioning options are still available inside the nested containers.

For more information
https://docs.microsoft.com/en-us/powerapps/maker/canvas-apps/controls/control-container
https://sharepains.com/2018/03/19/powerapps-grouping-fields-on-forms/