> Create a Visualforce page that you want to open as a popup window. > Create a custom button that will open the Visualforce page. To create a custom button, go to the object's setup page, click on Buttons, Links, and Actions, and then click on New Button or Link. > Give the button a label and name, select the Display Type as Detail Page Button, and select the Behavior as Display in new window. > Select the Content Source to be Visualforce Page and select the page from the list. > Save the button and add it to the page layout by dragging it to the Mobile & Lightning Actions section of the layout. > When a user clicks on the custom button, the Visualforce page will open as a popup window. You can also customize the Visualforce page to include functionality such as saving and closing the popup window
> Create a Visualforce page that you want to open as a popup window.
> Create a custom button that will open the Visualforce page. To create a custom button, go to the object's setup page, click on Buttons, Links, and Actions, and then click on New Button or Link.
> Give the button a label and name, select the Display Type as Detail Page Button, and select the Behavior as Display in new window.
> Select the Content Source to be Visualforce Page and select the page from the list.
> Save the button and add it to the page layout by dragging it to the Mobile & Lightning Actions section of the layout.
> When a user clicks on the custom button, the Visualforce page will open as a popup window. You can also customize the Visualforce page to include functionality such as saving and closing the popup window
Related:
https://developer.salesforce.com/forums/?id=906F0000000AN8uIAG
https://salesforce.stackexchange.com/questions/211271/save-and-close-vf-page-pop-up-on-single-click
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