What is a Widget?
Many widget providers will offer a quick install to Typepad option. Feedburner - including the email subscription widget - and WidgetBox are two of the services which offer a quick install to Typepad.
Other widget providers may provide you with HTML code to add to your blog. Using the Embed Your Own HTML module at Design > Content, you can add the code to your blog's sidebar.
If you are using the Chroma Theme, you will need to use the Custom Sidebar option on the Design tab to add the HTML for the widget.
Widgets and Advanced Templates
The quick install option for widgets can not be automatically added to Advanced Templates the way they can with Basic templates. However, you can visit the website for the Widget to retrieve the HTML, which can be added directly to the sidebar template or using a Notes TypeList.
Widgets and Mixed Media Layouts
With a Mixed Media Layout, a widget can be added to your blog by copying the widget code into a Notes TypeList. The quick install option for widgets is not available with a Mixed Media Layout.
Deleting a Widget
To delete a widget, go to Design > Content and locate the widget that you wish to delete. Click the red X at the corner of the module. Finally click Save Changes to update your blog.