Страдателен залог (Passive Voice)

"Семинар" is a singular masculine noun, so you need to use the singular masculine form "воден"

"Храна" is a singular feminine noun, so you need to use the singular feminine form "поръчана"

"Дете" is a singular neuter noun, so you need to use the singular neuter form "обичано"

"Сметка" is a singular feminine noun, so you need to use the singular feminine form "платена"

"Гости" is a plural noun, so you need to use the plural form "посрещнати"

"Задачи" is a plural noun, so you need to use the plural form "дадени"

"Съобщение" is a singular neuter noun, so you need to use the singular neuter form "изпратено"

"Места" is a plural noun, so you need to use the plural form "избрани"

"Билет" is a singular masculine noun, so you need to use the singular masculine form "купен"

"Врата" is a singular feminine noun, so you need to use the singular feminine form "заключена"