i have a simple database where i want to sum Amount of one one text box at the footer of my form textbox. Am using access as the database

And what part is giving you trouble?

i want the text box in my footer to show grand total whener i add new record

That's not the real problem. For VB, you could write an on change event handler that you sum it up and change the text box value as you wish. I often find folk struggling with this if they didn't complete a programming course or finish a book on programming in vb.net.

Answer: Use an on change event handler.

are you helping or judging? i havent gone to a programming course just learning on myself

Your choice. Now that I know you haven't completed eiither I hope you'll research the on change event and code that to do what you want.

Typically, if you want to display multirow data from a database you use a DataGridView rather than a Textbox. I'm assuming multirow otherwise you wouldn't need to do a sum.

O.K. I assume that you have added a totalsum row to your database which will give you a field that contains the total. If not then check this out:
https://www.gcflearnfree.org/access2016/how-to-create-calculated-fields-and-totals-rows/1/

To display this one field in your textbox you need a query against your database and display the result. Here is how to do this:
https://www.daniweb.com/programming/software-development/threads/461537/how-to-show-access-database-value-in-textbox