The content of an Entry widget can be modified programmatically with the insert() method, which takes two arguments:

• index: The position to insert the text; note that entry positions are 0-indexed
• string: The text to insert

A common pattern to reset the content of an entry with a default value can be achieved with a combination of delete() and insert():

entry.delete(0, tk.END) 
entry.insert(0, "default value") 

Another pattern is to append the text in the current position of the text cursor. Here, you can use the INSERT constant instead of having to calculate the numerical index:

entry.insert(tk.INSERT, "cursor here")

Like the Button class, the Entry class also accepts the relief and state options to modify its border style and state. Keep in mind that calls to delete() and insert() are ignored when the state is "disabled" or "readonly".