Русско-англо-русский юридический словарь

customs declaration – a statement showing goods being imported on which duty will have to be paid

Example: to fill in a customs declaration form (BusinessDictionary)

All goods imported into Bosnia-Herzegovina must be accompanied by a customs declaration, completed in Bosnian, Serbian or Croatian and submitted by the person named on the waybill or their authorised representative. (johnshirleyltd.co.uk)

Even with a Canada style zero tariffs, zero quotas deal, the UK will leave the European single market and single customs area once the transition is over on December 31, meaning businesses will need to make a projected 215m more customs declarations annually. (Financial Times)