Enter insert mode after the text specified by a motion. Requires vim-operator-user.
See also: vim-operator-insert
The plugin does not define any mappings. Define one like this:
map <Space>a <Plug>(operator-append)
<Space>ai"to append inside double quotes.<Space>aitto append inside a tag.<Space>aatto append after an ambient tag.<Space>af(to append after the next opening bracket.