You have to do it by mail and it has to be postmarked today (05/01). If you live in a qualified disaster area and you file between 04/15/25 and 05/01/25, the IRS will not impose a penalty. You can print and mail it; the form is linked at the bottom of this post.
If you need an extension through 10/15/25, you must file the extension on paper. See this IRS notice >> Further Tax Filing Extensions Available
Form 4868 and instructions included