You can’t put “Submit” buttons in a memo field. The memo field is designed to contain “Rich HTML formatted text” not HTML forms which it appears you are trying to do.
In a section grid I have a memo field. I can not edit it with any command, double click, etc.
Drag the memo field from the columns panel onto the page and an editable webview will be created under your grid. As you navigate records in the grid the webview contents will be refreshed. You may have to relate the grid to the webview section using the relationship builder.
Click on the webview to edit the memo.
Why does a memo field in a grid appear as a Link? (implying that something will happen when you click on it)
When you shift+Click+drag a table onto a page a grid section is created.
Double click on the section header and you will see some attributes for a “Split Screen” grid.