How to delete call history from TomTom Go 620?

The steps to delete browsing history vary depending upon the browser from which you wish to delete the history. To know more, you can refer to the following links:
For Internet Explorer:
http://windows.microsoft.com/en-in/internet-explorer/manage-delete-browsing-history-internet-explorer#ie=ie-11
For Google Chrome:
https://support.google.com/chrome/answer/95589?hl=en
For Mozilla Firefox:
https://support.mozilla.org/en-US/kb/delete-browsing-search-download-history-firefox#w_how-do-i-clear-my-history

GuruAid.com

http://download.tomtom.com/open/manuals/ttnpalmone/ttnpalmone_manual_uk.pdf this should help a pdf manual
happy new year

Link to instructions in the language of your choice
http://download.tomtom.com/open/manuals/start_60/manual.htm

You should have received an instruction manual with the TomTom' use it. If not, you should have. You can download the Reference Guide in PDF format from the TomTom website. The Reference Guide contains detailed information and full instructions for your TomTom product.

http://download.tomtom.com/open/manuals/non-LIVE/html/en-gb/index.htm#WelcometonavigationwithTomTom-Nav3.htm

windows key+r type %appdata%/skype delete everything in that folder

no one can access your account but you.
so if someone steals your tomtom device they will not know your tomtom account.
just keep the account for history purposes if you have made any payments on it.

please tell me how to delete address from the tomtom system

Microsoft Internet Explorer users
Viewing History Microsoft Internet Explorer 7.x users can view their history files by clicking the "Tools" menu, "Internet Options", clicking the "Settings" button under the Browsing history, and then clicking the "View Files" button. Microsoft Internet Explorer 6.x users can view their history files by clicking the "Tools" menu, "Internet Options", clicking the "Settings" button, and then clicking the "View Files" button.
Deleting History Microsoft Windows users running Microsoft Internet Explorer 6.x and 7.x can delete their history files by clicking the "Tools" menu, "Internet Options", and clicking the "Delete Files" or "Delete" button. Users also have the option of automatically deleting files each time the close the browser window by clicking the "Advanced" tab and checking "Empty Temporary Internet Files folder when browser is closed" under the "Security" section. Microsoft Internet Explorer 4.x users on an Apple Macintosh can delete the history by clicking the "Hard Drive" icon, "System",  "Preferences", "Explorer", and moving the history file into the trash. Microsoft Internet Explorer 3.02 and lower users can delete their history by clicking the "View" menu, "Options", open the tab "Advanced", click the "Settings" tab, and click the "Empty Folder" button.
Mozilla Firefox users
Viewing History
Press Ctrl + H to open the left-side history bar.
or 
Click History at the top of the window.
or
Users using earlier versions of Mozilla Firefox can also view their history by clicking "Go" and clicking "History."
Deleting History
Mozilla Firefox  users can clear their history by clicking the "Tools" menu, "Options", clicking the "Piracy" button, and under "History" click the "Clear" or "Clear Now" button.
or
Press CTRL + Shift + DEL to open the Clear Data Window.
Netscape users
Viewing History Microsoft Windows users can view history by first opening Netscape and click the "Edit" menu, "Preferences", "History", and view the location where Netscape is storing your files. Next, open this folder within Explorer.
Deleting History Netscape users can delete their history files by clicking the "Edit" menu, "Preferences", "History", and click the "Clear History" button.
Opera users
Viewing History
Users can view their history files by opening the "cache" folder within their opera folder. Microsoft Windows users can often find this within "C:\Program files\Opera\ ." If you're unable to locate the cache within this directory try opening the  "C:\Documents and Settings\**HOPE**\Application Data\Opera\Opera\profile" folder, where **HOPE** is the name of the username you use to log into Windows.
Deleting History
Opera users can delete their history by clicking the "File" menu, "Preferences", "History", and click "Empty now" button. In addition, users can check "Empty on exit" if they wish for this task to occur each time they exit the browser.

Do you mean on a ONE XL, XLS, or XL 330S? Do you mean simple deletion of history, or actual files on the device?

For deleting history, you can go into the preferences menu and Reset the Device back to Factory Settings. Say that you're sure 2x and its all cleared.

For more advanced deletion of files...

If you have the USB cord, connect it to your computer. Download and install the TomTom HOME software and register your device. From there, you can access the contents of your device and download new data or delete old files.

What are you trying to delete?