To automatically convert text that contains spaces or other "illegal" URL characters, put it inside a [URL] context. Certain letters, such as spaces, colons, and the equals sign (=) are not allowed inside URLs unless they are first converted to hexadecimal form.
Example (normally you would put the following text into a .tpl file on your server and use a web browser to link to it):
In the example above, the displayed text will be
This context is most often used with [sku] fields that represent the name of a picture of a product, as in <img src="[sku].gif">, because many times a product sku will have "illegal" characters in it.
[URL] is also often used to create predefined hyperlink-style searches, as in <a href="xx.tpl?command=search&db=xxx.db&eqNAMEdata=Grant%20Hulbert">. Sometimes you will want to create this kind of HTML dynamically using text from a field in a database, like so: