Commenting on the decision by the Northern Ireland Public Prosecution Service, Defence Secretary Gavin Williamson said:
"We are indebted to those soldiers who served with courage and distinction to bring peace to Northern Ireland.
"The welfare of our former service personnel is of the utmost importance and we will offer full legal and pastoral support to the individual affected by today’s decision.
"This includes funding all his legal costs and providing welfare support.
“The Ministry of Defence is working across Government to drive through a new package of safeguards to ensure our armed forces are not unfairly treated.
“And the Government will urgently reform the system for dealing with legacy issues.
"Our serving and former personnel cannot live in constant fear of prosecution.”
John Kelly, whose 17-year-old brother Michael was killed, said many had received a "terrible disappointment".
But he welcomed the positive news for the six families impacted by the decision to prosecute soldier F.
"Their victory is our victory," he said.
"We have walked a long journey since our fathers and brothers were brutally slaughtered on the streets of Derry on Bloody Sunday, over that passage of time all the parents of the deceased have died - we are here to take their place."
Mr Kelly highlighted there were legal means of challenging the decisions not to prosecute:
"The Bloody Sunday families are not finished yet."
Before the charges were announced, the families gathered outside The Museum of Free Derry, just yards from where the killings took place 47 years ago, and marched together to a city centre hotel to hear whether charges will be brought.
Mickey McKinney's oldest brother Willie was a fun-loving amateur photographer shot dead while he filmed the march.
Mr McKinney walked in the front line of families clutching a photo of his brother bearing the message "Justice for William McKinney".
He has been in the front line of campaigning for answers for decades.
Mr McKinney said: "It is important to point out that justice for one family is justice for all of us."
Soldier F is to be charged with murdering his brother and James Wray.
Mr Wray's brother John, 57, said: "David Cameron said it was unjustified and, I am not a lawyer but unjustified homicide, there is a term for that - and it is murder."
A public inquiry conducted by a senior judge shortly after the deaths was branded a whitewash by the dead victims' families, and thus began a campaign for a new public inquiry.
Families of the dead sought to right the wrongs of false claims that their loved ones had been armed.
A fresh probe was eventually ordered by former prime minister Tony Blair in 1998.
A decade-long investigation by Lord Saville of Newdigate concluded that the troops killed peaceful protesters and seriously criticised the decision to send them into the Bogside estate in vehicles.
Following the inquiry's conclusion in 2010, then-Prime Minister David Cameron said the killings were unjustified and unjustifiable.
An investigation by the Police Service of Northern Ireland (PSNI) followed the £195 million inquiry and files on 18 soldiers were submitted to prosecutors in 2016 and 2017 for consideration. One former soldier has since died.
Four other soldiers included in the Saville Report died before police had completed their investigation.
Papers before prosecutors included 668 witness statements and numerous photos, video and audio evidence.