Navigate to your Wizard101 Folder (usually Program Files/KingsIsle Entertainment/Wizard101) then go to the Bin Folder then select "WizardClient.Log". Then just drag the file into the body of the email.
If this is too large for your email server to attach or send, then open the game folder, go to the the bin folder again and locate the WizardClient.log. Right click on the log file and select Save as Zip (or similar wording - will vary depending on your specific operating system). Then, go back to your email and attach the newly zipped wizardclient.log.zip file.