S.C. Code § 7-15-365
The board of voter registration and elections of each county must be furnished by the municipal election commission of each municipality holding an election or the executive committee of a municipal party holding a primary, a sufficient number of ballots, envelopes, and instructions to the absentee voter not to exceed fifteen percent of the number of registered voters in the municipality and sufficient postage to enable the board of voter registration and elections to deliver materials to qualified electors desiring to vote by absentee ballot. The envelope required by item (4) of Section 7-15-370 must bear the return address of the county board of voter registration and elections. If an absentee ballot is not available at the time the voter requests it, the board of voter registration and elections must provide a blank ballot to allow the voter to write in his:
S.C. Code § 7-15-365