It is very difficult for independents and third parties to get onto U.S. House ballots in Georgia. From a post on Ballot Access News by Richard Winger:

During the years 1970 through 2016, there have been 10,463 regularly-scheduled U.S. House elections (this includes Delegate from the District of Columbia for the years 1972-2016; there was no such election in D.C. in 1970). During those years, there have been 7,220 U.S. House candidates on the ballot who were not the nominees of the Democratic or Republican Parties.

The state with the fewest non-Democratic, non-Republican candidates on the ballot for U.S. House during those years has been Georgia. There has been only one individual, Billy McKinney (Cynthia McKinney’s father), who ever appeared on a regularly-scheduled Georgia ballot in the period 1970 to the present and who was not a Democratic or Republican nominee. He was able to qualify because the normal Georgia petitioning requirement was suspended the year he ran, 1982, in the two Atlanta districts, due to late redistricting.

Read more from that article here. Also of note, a recent example shows that according to the state website:

Eight candidates have officially qualified for the April 18, 2017 Special Election for State Senate District 32. This week, Secretary of State Brian Kemp hosted qualifying to fill the seat vacated by Judson Hill from the Georgia Senate.

Qualifying closed at 1 p.m. today. Five Republican candidates – Hamilton Beck, Matt Campbell, Roy Daniels, Kay Kirkpatrick, and Gus Makris – qualified for the race. Three Democratic candidates – Christine Triebsch, Exton Howard, and Bob Wiskind – also qualified for the race.

Also, January 1, 2018 is the earliest day to file and publish a notice of intention to be a write-in candidate in the General Election and January 11, 2018 is the earliest day to circulate nomination petition for General Election for Independent/Political Body Candidates.