article link: https://digitaldrummerj.me/hugo-create-rss-feed/

rss.html

{{- $pctx := . -}}
{{- if .IsHome -}}{{ $pctx = .Site }}{{- end -}}
{{- $pages := slice -}}

// change file code in default template

{{- if or $.IsHome $.IsSection -}}
{{- $pages = (where (where $pctx.RegularPages ".Section" "posts") "Kind" "page")  -}}
{{- else -}}
{{- $pages = (where (where $pctx.Pages ".Section" "posts") "Kind" "page")  -}}
{{- end -}}

{{- $limit := .Site.Config.Services.RSS.Limit -}}
{{- if ge $limit 1 -}}
{{- $pages = $pages | first $limit -}}
{{- end -}}
{{- printf "<?xml version=\"1.0\" encoding=\"utf-8\" standalone=\"yes\"?>" | safeHTML }}
<rss version="2.0" xmlns:atom="http://www.w3.org/2005/Atom">
  <channel>
    <title>{{ if eq  .Title  .Site.Title }}{{ .Site.Title }}{{ else }}{{ with .Title }}{{.}} on {{ end }}{{ .Site.Title }}{{ end }}</title>
    <link>{{ .Permalink }}</link>
    <description>Recent content {{ if ne  .Title  .Site.Title }}{{ with .Title }}in {{.}} {{ end }}{{ end }}on {{ .Site.Title }}</description>
    <generator>Hugo -- gohugo.io</generator>{{ with .Site.LanguageCode }}
    <language>{{.}}</language>{{end}}{{ with .Site.Author.email }}
    <managingEditor>{{.}}{{ with $.Site.Author.name }} ({{.}}){{end}}</managingEditor>{{end}}{{ with .Site.Author.email }}
    <webMaster>{{.}}{{ with $.Site.Author.name }} ({{.}}){{end}}</webMaster>{{end}}{{ with .Site.Copyright }}
    <copyright>{{.}}</copyright>{{end}}{{ if not .Date.IsZero }}
    <lastBuildDate>{{ .Date.Format "Mon, 02 Jan 2006 15:04:05 -0700" | safeHTML }}</lastBuildDate>{{ end }}
    {{- with .OutputFormats.Get "RSS" -}}
    {{ printf "<atom:link href=%q rel=\"self\" type=%q />" .Permalink .MediaType | safeHTML }}
    {{- end -}}
    {{ range $pages }}
    <item>
      <title>{{ .Title }}</title>
      <link>{{ .Permalink }}</link>
      <pubDate>{{ .Date.Format "Mon, 02 Jan 2006 15:04:05 -0700" | safeHTML }}</pubDate>
      {{ with .Site.Author.email }}<author>{{.}}{{ with $.Site.Author.name }} ({{.}}){{end}}</author>{{end}}
      <guid>{{ .Permalink }}</guid>
      <description>{{ .Summary | html }}</description>
    </item>
    {{ end }}
  </channel>
</rss>