By default, Formstack forms take up one column. However, you can change this by clicking on the Form Extras tab at the top of your screen when on the Build tab of the form. Under layout, you can choose the number of columns you want your form to have. You can have anywhere from one to four columns on your form.
Sections & Multi-Column Forms
If you want part of your form to have three columns and part of it to have four columns, this can be done, even if you have your form set up as one or two columns by default. The way you can do this is with Sections.
Add a new Section to your form (leave it blank if you don't want users to actually see it) and choose the number of columns for that section from the drop-down "Columns" menu. Now, any fields you place under that section will be displayed in the number of columns you chose. To end this effect or create a "stacked" look with your columns, add a second section to the part of your form you want to display a different number of columns on. Each new section on your form can display whatever number of columns you would like, allowing you to have 1-column, 2-column, 3-column, and 4-column sections all on the same form.
Expand Fields Across Columns
Let's say you have a three-column section, but you only need two fields, a name and an email field on the first row of the section. You can expand the name field to fill multiple columns with a click of a button. Click on the field you'd like to edit, then choose how many columns you'd like the field to span by clicking on the "Column Span" dropdown list.