separate sheet; attached document; enclosure
Refers to a document or sheet that is separate from the main body, often attached or enclosed with a letter, report, or email. Common in business and formal writing.
Please see the attached sheet for details.
別紙にてご案内申し上げます。
We will inform you in a separate document.
別紙 means an attached separate sheet or document of any kind, whereas 別表 specifically refers to an attached table or chart.
Compound of 別 (separate) and 紙 (paper). The reading べっし is a standard on'yomi combination.