Quick answer
On a Samsung Galaxy phone, long-press an empty area of the home screen, choose Widgets and select the widget from its installed app. Place it where the One UI Home grid has enough free cells. Some Samsung widgets support resizing or stacking while others do not. If a particular app is missing, check that the app actually provides a widget and complete any required app setup before changing launcher settings.
Add a widget using Samsung's home-screen menu
On a Galaxy phone running Samsung's One UI home launcher, return to the home screen and press and hold a blank area. Choose Widgets, find the app you want and select its widget. Samsung's picker can offer several sizes or designs for the same app. Choose one and tap Add, then move it where you want it.
If the menu has different labels on your phone, first check whether you are using Samsung's own Home launcher or a different installed launcher. Screens and options change with One UI version and device model. Samsung's official Galaxy widget instructions show the basic process.
Move or resize it without starting over
Press and hold the placed widget to enter editing mode. If that particular widget supports resizing, an outline or handles appear. Drag the available edges rather than trying to scale the text inside the widget. Some apps expose additional appearance settings after a long press, but color and transparency controls are not universal.
Leave enough room between widgets and app icons. A design that appears wide in the preview may be constrained by the Samsung home-screen grid. Try an empty page if you are unsure whether the size is the issue. Our widget size guide explains how to plan the available cells.
When the widget cannot be moved
Check whether Lock Home screen layout is enabled in Samsung's Home screen settings. A locked layout can prevent rearranging icons or widgets. Change that setting only if you intentionally want to edit the arrangement, and re-enable it afterwards if you prefer preventing accidental moves.
Also distinguish Remove from Uninstall. Removing a widget from the home screen is not the same as deleting the app. If a widget is missing from the picker entirely, see widget not showing in the picker.
Consider stacks when space is tight
Some Samsung Galaxy phones let you stack compatible widgets so several share one home-screen position. On supported versions, long-press a widget and look for Create stack or a similar option. If no stack option appears, your current software or widget combination might not support it. Samsung explains the behavior in its widget and stack help.
Keep frequently needed information visible without swiping. For example, a calendar entry you check every morning may deserve its own spot rather than a hidden card in a stack.