In stitching we have 2 options i.e. Ready to wear and Made to measure.

In case you opt for Ready to wear, you would have to select the size from the available sizes at the time of placing an order.

However, in case you opt for Made to measure, you may place an order without submitting the measurements. Once you select Made to measure you would see an option stating "Submit Measurement Later". You can click on the same and proceed further.