Use one primary reading path through a form

Give the form one primary path from first question to final action. Use an overall single-column layout, with side-by-side fields only when they form one familiar unit.

Multicolumn forms can make field order and relationships ambiguous. Baymard's checkout testing found that single-column layouts reduced skipped or misinterpreted fields, while allowing small groups of closely related inputs on one row.[1] The distinction matters: “one column” does not require every field to consume the full viewport width.