May 2020 update: Bezier Envelope Extension not currently compatible with Inkscape 1.x, unfortunately.
To download a free Inkscape template of ready made shapes, click here.
2. To install the extension, copy both the bezierenvelope.inx and the bezierenvelope.py file into the folder/directory indicated.
-In Windows: Copy the two files into: C:Program Files\Inkscape\share\extensions
( Assuming that your Inkscape is located at C:Program Files\Inkscape)
-On MacOS for Inkscape .48 or earlier : “/Applications/Inkscape.app/Contents/Resources/extensions”
-In MacOS for Inkscape .91: “/Applications/Inkscape.app/Contents/Resources/share/Inkscape/extensions”
To get to either location on the Mac, you can use the Finder’s “go to folder” feature, in the Go menu and copy/paste the string inside the quotation marks
If you can’t find the extensions folder using this path, you can open Inkscape and look under Preferences>System>Inkscape Extensions to find your specific path
3. Re-open Inkscape and verify that Bezier Envelope appears under Extensions menu > Modify Path submenu.
If you need more help installing the extension, here are some videos