How can I treat policeman heel?

Orthotics. These help anyone standing/walking long term a during work by restoring proper joint alignment and reducing the stress and workload of tendons which support the foot. Custom inserts are usually best for this line of work. Injections and other methods are extremely helpful in acute pain flares.
Refer to answer. This is usually called plantar fasciaitis. The cause is very complicated. Can try a good insole, with cold pack and stretch. If that does not work, then therapy and cortison injection is the last on the agenda.If persist then see your physician.
Visco heels. High quality silicone heel cups are best to decrease the trauma to the heels (bauerfeind, blue-dot, ...). Regular heel and plantar fascia stretches are helpful too, as is ice massage and activity modification. Custom orthotics are rarely necessary unless there is underlying foot alignment abnormality.