What do you mean by sending insoles?
In addition to comfort, insoles may also have specific uses. In some occasions, such as weddings, exams, job hunting and other important days, sending insoles is regarded as a kind of "auspicious thing", which can bring good luck and smoothness. So if someone gives you insoles, you might as well put them on as far as possible on the premise that the appearance color conforms to the occasion, so as to help on important days.
A doormat can also be a polite gesture. In some Asian countries, such as Japan, South Korea and China, sending insoles is regarded as an act of respect and courtesy. It may be considered rude to meet empty-handed, but giving a pair of shoe pads can express your heart. So if you travel or work in these areas and want to establish a good relationship with local people, sending insoles may be a good choice.