If you are unable to share for assessment to a workspace or assignment there will be a red cross showing next to the workspace or assignment in the share panel.  There are a number of reasons why you might be unable to submit:

1. You have already submitted the work once

- any asset can only be submitted once to a workspace.  Once submitted, a live link is established between the workspace and the asset in your Asset Store.  This live link means that any changes you make to the asset are visible on the workspace without having to submit again.  

2.  You are trying to submit the wrong asset type

- a workspace can be set to only accept particular asset types.  If it has been set to accept workbooks and you are trying to submit a webfolio you will be unable to submit.  The share panel will contain information about the accepted asset types if restrictions apply.

3.  You have already submitted the maximum number of permitted submissions

- a workspace can be set to only accept a certain number of submissions per member.  If it has been set to accept 2 submissions per member and you are trying to submit a third piece of work you will be unable to submit.  The share panel will contain information about the number of permitted submissions.

4.  The submission deadline has passed

- deadlines can be set for a workspace and if the submission deadline has passed you will be unable to submit.  The share panel will contain information about important dates and will indicate if the deadline has passed.

In any of the above apply you may need to contact your tutor or lecturer.