This is an easy one

STEP 1 - CREATE TEXT PROCESSOR IN AUTOSHARE

• Open the main AutoShare App
• Tap the Manage Text Processors option
• Add a new Text Processor
• Call it Insert Location
• Give it an icon that's related to location like this one for example
• Set it to time out after 15 seconds. You can change this to whatever time you think it'll take Tasker to get your location

STEP 2 - CREATE TASKER PROFILE

• Create a new profile in Tasker with the AutoShare Process text event condition
• Select the newly created Insert Location text processor
• Accept and create an entry task for the profile

STEP 3 - REPORT LOCATION BACK TO AUTOSHARE

• Add a new AutoShare Process Text Tasker action
• in the Processed Text field write %LOC

%LOC is the Tasker variable that contains your current GPS location. If you want to use a less precise location which is faster to obtain, use %LOCN instead
If you want to send a link to Google Maps instead of just the location you can use http://maps.google.com/maps?q=%LOC That way the person can simply click on the link

• Accept the task and exit Tasker to save

STEP 4 - TEST

Text processors can only work with selected text so to insert your location you need to select some text first. In this example I wrote a simple space character to be able to select and replace it with the location.

• Open a messaging app
• Write 1 space character and select it
• Select the 3-dot menu icon
• Select AUTOSHARE
• Select the newly created Insert Location text processor
• Watch as the space character you selected is replaced by your current location